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<body>
<div class="head">
<p>
<a href="http://www.w3.org/">
<img src="http://www.w3.org/Icons/w3c_home" alt="W3C" height="48" width="72">
</a>
</p>
<h1 class="title" id="title">
JSON-LD
1.0
</h1>
<h2 id="subtitle">
A
JSON-based
Serialization
for
Linked
Data
</h2>
<h2 id="final-community-group-specification-22-february-2013">
Final
Community
Group
Specification
<del class="diff-old">02
</del>
<ins class="diff-chg">22
</ins>
February
2013
</h2>
<dl>
<dt>
Latest
editor's
draft:
</dt>
<dd>
<a href="http://dvcs.w3.org/hg/json-ld/raw-file/default/spec/latest/json-ld-syntax/index.html">
http://dvcs.w3.org/hg/json-ld/raw-file/default/spec/latest/json-ld-syntax/index.html
</a>
</dd>
<dt>
Editors:
</dt>
<dd rel="bibo:editor" inlist="">
<span typeof="foaf:Person">
<a rel="foaf:homepage" property="foaf:name" content="Manu Sporny" href="http://manu.sporny.org/">
Manu
Sporny
</a>,
<a rel="foaf:workplaceHomepage" href="http://digitalbazaar.com/">
Digital
Bazaar
</a>
</span>
</dd>
<dd rel="bibo:editor" inlist="">
<span typeof="foaf:Person">
<a rel="foaf:homepage" property="foaf:name" content="Gregg Kellogg" href="http://greggkellogg.net/">
Gregg
Kellogg
</a>,
<a rel="foaf:workplaceHomepage" href="http://kellogg-assoc.com/">
Kellogg
Associates
</a>
</span>
</dd>
<dd rel="bibo:editor" inlist="">
<span typeof="foaf:Person">
<a rel="foaf:homepage" property="foaf:name" content="Markus Lanthaler" href="http://www.markus-lanthaler.com/">
Markus
Lanthaler
</a>,
<a rel="foaf:workplaceHomepage" href="http://www.tugraz.at/">
Graz
University
of
Technology
</a>
</span>
</dd>
<dt>
Authors:
</dt>
<dd rel="dcterms:contributor">
<span typeof="foaf:Person">
<a rel="foaf:homepage" property="foaf:name" content="Manu Sporny" href="http://digitalbazaar.com/">
Manu
Sporny
</a>,
<a rel="foaf:workplaceHomepage" href="http://digitalbazaar.com/">
Digital
Bazaar
</a>
</span>
</dd>
<dd rel="dcterms:contributor">
<span typeof="foaf:Person">
<a rel="foaf:homepage" property="foaf:name" content="Dave Longley" href="http://digitalbazaar.com/">
Dave
Longley
</a>,
<a rel="foaf:workplaceHomepage" href="http://digitalbazaar.com/">
Digital
Bazaar
</a>
</span>
</dd>
<dd rel="dcterms:contributor">
<span typeof="foaf:Person">
<a rel="foaf:homepage" property="foaf:name" content="Gregg Kellogg" href="http://greggkellogg.net/">
Gregg
Kellogg
</a>,
<a rel="foaf:workplaceHomepage" href="http://kellogg-assoc.com/">
Kellogg
Associates
</a>
</span>
</dd>
<dd rel="dcterms:contributor">
<span typeof="foaf:Person">
<a rel="foaf:homepage" property="foaf:name" content="Markus Lanthaler" href="http://www.markus-lanthaler.com/">
Markus
Lanthaler
</a>,
<a rel="foaf:workplaceHomepage" href="http://www.tugraz.at/">
Graz
University
of
Technology
</a>
</span>
</dd>
<dd rel="dcterms:contributor">
<span typeof="foaf:Person">
<a rel="foaf:homepage" property="foaf:name" content="Niklas Lindström" href="http://neverspace.net/">
Niklas
Lindström
</a>
</span>
</dd>
</dl>
<p>
This
document
is
also
available
in
this
non-normative
format:
<a class="alt-format" href="diff-20130202.html">
diff
to
previous
version
</a>
</p>
<p class="copyright">
<a href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">
Copyright
</a>
©
2010-2013
the
Contributors
to
the
JSON-LD
1.0
Specification,
published
by
the
<a href="http://www.w3.org/2011/rdf-wg/">
RDF
Working
Group
</a>
under
the
<a href="https://www.w3.org/community/about/agreements/fsa/">
W3C
Community
Final
Specification
Agreement
(FSA)
</a>.
A
human-readable
<a href="http://www.w3.org/community/about/agreements/fsa-deed/">
summary
</a>
is
available.
</p>
<hr>
</div>
<section rel="bibo:chapter" resource="#abstract" typeof="bibo:Chapter" datatype="" property="dcterms:abstract" class="introductory" id="abstract">
<h2>
Abstract
</h2>
<p>
JSON
has
proven
to
be
a
highly
useful
object
serialization
and
messaging
format.
In
an
attempt
to
harmonize
the
representation
of
<a href="#dfn-linked-data" title="linked-data" class="tref internalDFN">
Linked
Data
</a>
in
JSON,
this
specification
outlines
a
common
JSON
representation
format
for
expressing
directed
graphs;
mixing
both
Linked
Data
and
non-Linked
Data
in
a
single
document.
</p>
</section>
<section rel="bibo:chapter" resource="#sotd" typeof="bibo:Chapter" id="sotd" class="introductory">
<h2>
Status
of
This
Document
</h2>
<p>
This
specification
was
published
by
the
<a href="http://www.w3.org/2011/rdf-wg/">
RDF
Working
Group
</a>.
It
is
not
a
W3C
Standard
nor
is
it
on
the
W3C
Standards
Track.
Please
note
that
under
the
<a href="https://www.w3.org/community/about/agreements/final/">
W3C
Community
Final
Specification
Agreement
(FSA)
</a>
other
conditions
apply.
Learn
more
about
<a href="http://www.w3.org/community/">
W3C
Community
and
Business
Groups
</a>.
</p>
<p>
This
document
has
been
under
development
for
over
25
months
in
the
JSON
for
Linking
Data
Community
Group.
The
document
has
recently
been
transferred
to
the
RDF
Working
Group
for
review,
improvement,
and
publication.
The
specification
has
undergone
significant
development,
review,
and
changes
during
the
course
of
the
last
25
months.
</p>
<p>
There
are
several
independent
<a href="http://json-ld.org/#impl">
interoperable
implementations
</a>
of
this
specification.
There
is
a
<a href="https://github.com/json-ld/json-ld.org/tree/main/test-suite">
fairly
complete
test
suite
</a>
and
a
<a href="http://json-ld.org/playground/">
live
JSON-LD
editor
</a>
that
is
capable
of
demonstrating
the
features
described
in
this
document.
While
development
on
implementations,
the
test
suite
and
the
live
editor
will
continue,
they
are
believed
to
be
mature
enough
to
be
integrated
into
a
non-production
system
at
this
point
in
time
with
the
expectation
that
they
could
be
used
in
a
production
system
within
the
next
year.
</p>
<p>
There
are
a
number
of
ways
that
one
may
participate
in
the
development
of
this
specification:
</p>
<ul>
<li>
If
you
want
to
make
sure
that
your
feedback
is
formally
addressed
by
the
RDF
Working
Group,
you
should
send
it
to
public-rdf-comments:
<a href="http://lists.w3.org/Archives/Public/public-rdf-comments/">
public-rdf-comments@w3.org
</a>
</li>
<li>
Ad-hoc
technical
discussion
primarily
occurs
on
the
public
community
mailing
list:
<a href="http://lists.w3.org/Archives/Public/public-linked-json/">
public-linked-json@w3.org
</a>
</li>
<li>
<a href="http://json-ld.org/minutes/">
Public
JSON-LD
Community
Group
teleconferences
</a>
are
held
on
Tuesdays
at
1500UTC
every
week.
</li>
<li>
RDF
Working
Group
teleconferences
are
held
on
Wednesdays
at
1500UTC
every
week.
Participation
is
limited
to
RDF
Working
Group
members.
</li>
<li>
Specification
bugs
and
issues
should
be
reported
in
the
<a href="https://github.com/json-ld/json-ld.org/issues">
issue
tracker
</a>
if
you
do
not
want
to
send
an
e-mail
to
the
public-rdf-comments
mailing
list.
</li>
<li>
<a href="https://github.com/json-ld/json-ld.org/tree/main/spec">
Source
code
</a>
for
the
specification
can
be
found
on
Github.
</li>
<li>
The
<a href="http://webchat.freenode.net/?channels=json-ld">
#json-ld
</a>
IRC
channel
is
available
for
real-time
discussion
on
irc.freenode.net.
</li>
</ul>
</section>
<section id="toc">
<h2 class="introductory">
Table
of
Contents
</h2>
<ul class="toc">
<li class="tocline">
<a class="tocxref" href="#introduction">
<span class="secno">
1.
</span>
Introduction
</a>
<ul class="toc">
<li class="tocline">
<a class="tocxref" href="#how-to-read-this-document">
<span class="secno">
1.1
</span>
How
to
Read
this
Document
</a>
</li>
</ul>
</li>
<li class="tocline">
<a class="tocxref" href="#design-goals-and-rationale">
<span class="secno">
2.
</span>
Design
Goals
and
Rationale
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#terminology">
<span class="secno">
3.
</span>
Terminology
</a>
<ul class="toc">
<li class="tocline">
<a class="tocxref" href="#general-terminology">
<span class="secno">
3.1
</span>
General
Terminology
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#syntax-tokens-and-keywords">
<span class="secno">
3.2
</span>
Syntax
Tokens
and
Keywords
</a>
</li>
</ul>
</li>
<li class="tocline">
<a class="tocxref" href="#conformance">
<span class="secno">
4.
</span>
Conformance
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#basic-concepts">
<span class="secno">
5.
</span>
Basic
Concepts
</a>
<ul class="toc">
<li class="tocline">
<a class="tocxref" href="#the-context">
<span class="secno">
5.1
</span>
The
Context
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#iris">
<span class="secno">
5.2
</span>
IRIs
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#node-identifiers">
<span class="secno">
5.3
</span>
Node
Identifiers
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#specifying-the-type">
<span class="secno">
5.4
</span>
Specifying
the
Type
</a>
</li>
</ul>
</li>
<li class="tocline">
<a class="tocxref" href="#advanced-concepts">
<span class="secno">
6.
</span>
Advanced
Concepts
</a>
<ul class="toc">
<li class="tocline">
<a class="tocxref" href="#compact-iris">
<span class="secno">
6.1
</span>
Compact
IRIs
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#typed-values">
<span class="secno">
6.2
</span>
Typed
Values
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#type-coercion">
<span class="secno">
6.3
</span>
Type
Coercion
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#advanced-context-usage">
<span class="secno">
6.4
</span>
Advanced
Context
Usage
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#interpreting-json-as-json-ld">
<span class="secno">
<del class="diff-old">6.4.1
</del>
<ins class="diff-chg">6.5
</ins>
</span>
Interpreting
JSON
as
JSON-LD
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#string-internationalization">
<span class="secno">
<del class="diff-old">6.5
</del>
<ins class="diff-chg">6.6
</ins>
</span>
String
Internationalization
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#overriding-vocab">
<span class="secno">
<del class="diff-old">6.6
</del>
<ins class="diff-chg">6.7
</ins>
</span>
Overriding
@vocab
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#property-generators">
<span class="secno">
<del class="diff-old">6.7
</del>
<ins class="diff-chg">6.8
</ins>
</span>
Property
Generators
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#iri-expansion-within-a-context">
<span class="secno">
<del class="diff-old">6.8
</del>
<ins class="diff-chg">6.9
</ins>
</span>
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Expansion
Within
a
Context
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#sets-and-lists">
<span class="secno">
<del class="diff-old">6.9
</del>
<ins class="diff-chg">6.10
</ins>
</span>
Sets
and
Lists
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#embedding">
<span class="secno">
<del class="diff-old">6.10
</del>
<ins class="diff-chg">6.11
</ins>
</span>
Embedding
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#named-graphs">
<span class="secno">
<del class="diff-old">6.11
</del>
<ins class="diff-chg">6.12
</ins>
</span>
Named
Graphs
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#identifying-blank-nodes">
<span class="secno">
<del class="diff-old">6.12
</del>
<ins class="diff-chg">6.13
</ins>
</span>
Identifying
Blank
Nodes
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#aliasing-keywords">
<span class="secno">
<del class="diff-old">6.13
</del>
<ins class="diff-chg">6.14
</ins>
</span>
Aliasing
Keywords
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#expanded-document-form">
<span class="secno">
<del class="diff-old">6.14
</del>
<ins class="diff-chg">6.15
</ins>
</span>
Expanded
Document
Form
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#compact-document-form">
<span class="secno">
<del class="diff-old">6.15
</del>
<ins class="diff-chg">6.16
</ins>
</span>
Compact
Document
Form
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#data-indexing">
<span class="secno">
<del class="diff-old">6.16
</del>
<ins class="diff-chg">6.17
</ins>
</span>
Data
Indexing
</a>
</li>
</ul>
</li>
<li class="tocline">
<a class="tocxref" href="#data-model">
<span class="secno">
A.
</span>
Data
Model
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#json-ld-grammar">
<span class="secno">
B.
</span>
JSON-LD
Grammar
</a>
<ul class="toc">
<li class="tocline">
<a class="tocxref" href="#grammar-node-object">
<span class="secno">
B.1
</span>
Node
Object
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#grammar-term-reference">
<span class="secno">
B.2
</span>
Term
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#grammar-language-map">
<span class="secno">
B.3
</span>
Language
Map
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#grammar-index-map">
<span class="secno">
B.4
</span>
Index
Map
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#grammar-expanded-values">
<span class="secno">
B.5
</span>
Expanded
Values
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#grammar-set-list">
<span class="secno">
B.6
</span>
List
and
Set
Values
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#grammar-context">
<span class="secno">
B.7
</span>
Context
Definition
</a>
</li>
</ul>
</li>
<li class="tocline">
<a class="tocxref" href="#relationship-to-rdf">
<span class="secno">
C.
</span>
Relationship
to
RDF
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#relationship-to-other-linked-data-formats">
<span class="secno">
D.
</span>
Relationship
to
Other
Linked
Data
Formats
</a>
<ul class="toc">
<li class="tocline">
<a class="tocxref" href="#turtle">
<span class="secno">
D.1
</span>
Turtle
</a>
<ul class="toc">
<li class="tocline">
<a class="tocxref" href="#prefix-definitions">
<span class="secno">
D.1.1
</span>
Prefix
definitions
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#embedding-1">
<span class="secno">
D.1.2
</span>
Embedding
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#lists">
<span class="secno">
D.1.3
</span>
Lists
</a>
</li>
</ul>
</li>
<li class="tocline">
<a class="tocxref" href="#rdfa">
<span class="secno">
D.2
</span>
RDFa
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#microformats">
<span class="secno">
D.3
</span>
Microformats
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#microdata">
<span class="secno">
D.4
</span>
Microdata
</a>
</li>
</ul>
</li>
<li class="tocline">
<a class="tocxref" href="#iana-considerations">
<span class="secno">
E.
</span>
IANA
Considerations
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#acknowledgements">
<span class="secno">
F.
</span>
Acknowledgements
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#references">
<span class="secno">
G.
</span>
References
</a>
<ul class="toc">
<li class="tocline">
<a class="tocxref" href="#normative-references">
<span class="secno">
G.1
</span>
Normative
references
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#informative-references">
<span class="secno">
G.2
</span>
Informative
references
</a>
</li>
</ul>
</li>
</ul>
</section>
<section id="introduction" class="informative">
<h2>
<span class="secno">
1.
</span>
Introduction
</h2>
<p>
<em>
This
section
is
non-normative.
</em>
</p>
<p>
<dfn id="dfn-linked-data" title="linked-data">
Linked
Data
</dfn>
is
a
technique
for
creating
a
network
of
inter-connected
data
across
different
documents
and
Web
sites.
In
general,
Linked
Data
has
four
properties:
1)&nbsp;it
uses
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>
to
name
things;
2)&nbsp;it
uses
HTTP
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>
for
those
names;
3)&nbsp;the
name
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>,
when
dereferenced,
provide
more
information
about
the
name;
and
4)&nbsp;the
data
expresses
links
to
data
on
other
Web
sites.
These
properties
allow
data
published
on
the
Web
to
work
much
like
Web
pages
do
today.
One
can
start
at
one
piece
of
Linked
Data,
and
follow
the
links
to
other
pieces
of
data
that
are
hosted
on
different
sites
across
the
Web.
</p>
<p>
JSON-LD
is
designed
as
a
lightweight
syntax
to
express
<a href="#dfn-linked-data" title="linked-data" class="tref internalDFN">
Linked
Data
</a>
in
JSON
[
<cite>
<a href="#bib-RFC4627" class="bibref">
RFC4627
</a>
</cite>
].
It
is
primarily
intended
to
be
a
way
to
use
Linked
Data
in
Web-based
programming
environments.
It
is
also
useful
when
building
interoperable
Web
services
and
when
storing
Linked
Data
in
JSON-based
storage
engines.
Since
JSON-LD
is
100%
compatible
with
JSON
the
large
number
of
JSON
parsers
and
libraries
available
today
can
be
reused.
Additionally
to
all
the
features
JSON
provides,
JSON-LD
introduces:
</p>
<ul>
<li>
a
universal
identifier
mechanism
for
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
objects
</a>
via
the
use
of
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>,
</li>
<li>
a
way
to
disambiguate
the
keys
used
between
multiple
JSON
documents
by
mapping
them
to
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>
via
a
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>,
</li>
<li>
a
mechanism
in
which
a
value
in
a
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
object
</a>
may
refer
to
a
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
object
</a>
on
a
different
site
on
the
Web,
</li>
<li>
the
ability
to
express
the
language
associated
with
a
<a href="#dfn-string" title="string" class="tref internalDFN">
string
</a>
</li>
<li>
a
way
to
associate
datatypes
with
values
such
as
dates,
times,
weights,
and
distances,
</li>
<li>
and
a
facility
to
express
one
or
more
directed
graphs,
such
as
a
social
network,
in
a
single
document.
</li>
</ul>
<p>
Developers
that
require
any
of
the
facilities
listed
above
or
need
to
serialize
an
RDF
graph
or
dataset
[
<cite>
<a href="#bib-RDF-CONCEPTS" class="bibref">
RDF-CONCEPTS
</a>
</cite>
]
in
a
JSON-based
syntax
will
find
JSON-LD
of
interest.
The
syntax
is
designed
to
not
disturb
already
deployed
systems
running
on
JSON,
but
provide
a
smooth
upgrade
path
from
JSON
to
JSON-LD.
</p>
<section id="how-to-read-this-document">
<h3>
<span class="secno">
1.1
</span>
How
to
Read
this
Document
</h3>
<p>
<em>
This
section
is
non-normative.
</em>
</p>
<p>
This
document
is
a
detailed
specification
for
a
serialization
of
Linked
Data
in
JSON.
The
document
is
primarily
intended
for
the
following
audiences:
</p>
<ul>
<li>
Software
developers
that
want
to
encode
Linked
Data
in
a
variety
of
programming
languages
that
can
use
JSON.
</li>
<li>
Software
developers
that
want
to
understand
the
design
decisions
and
language
syntax
for
JSON-LD.
</li>
<li>
Software
developers
that
want
to
implement
processors
and
APIs
for
JSON-LD.
</li>
</ul>
<p>
This
specification
does
not
describe
the
programming
interfaces
for
the
JSON-LD
Syntax.
The
specification
that
describes
the
programming
interfaces
for
JSON-LD
documents
is
the
JSON-LD
Application
Programming
Interface
[
<cite>
<a href="#bib-JSON-LD-API" class="bibref">
JSON-LD-API
</a>
</cite>
].
</p>
<p>
To
understand
the
basics
in
this
specification
you
must
first
be
familiar
with
JSON,
which
is
detailed
in
[
<cite>
<a href="#bib-RFC4627" class="bibref">
RFC4627
</a>
</cite>
].
</p>
</section>
</section>
<section id="design-goals-and-rationale" class="informative">
<h2>
<span class="secno">
2.
</span>
Design
Goals
and
Rationale
</h2>
<p>
<em>
This
section
is
non-normative.
</em>
</p>
<p>
A
number
of
design
goals
were
established
before
the
creation
of
this
markup
language:
</p>
<dl>
<dt>
Simplicity
</dt>
<dd>
No
extra
processors
or
software
libraries
should
be
necessary
to
use
JSON-LD
in
its
most
basic
form.
The
language
will
provide
developers
with
a
very
easy
learning
curve.
Developers
only
need
to
know
JSON
and
two
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keywords
</a>
(
<code>
@context
</code>
and
<code>
@id
</code>
)
to
use
the
basic
functionality
in
JSON-LD.
</dd>
<dt>
Compatibility
</dt>
<dd>
The
JSON-LD
markup
must
be
100%
compatible
with
JSON.
This
ensures
that
all
of
the
standard
JSON
libraries
work
seamlessly
with
JSON-LD
documents.
</dd>
<dt>
Expressiveness
</dt>
<dd>
The
syntax
must
be
able
to
express
directed
graphs,
which
have
been
proven
to
be
able
to
express
almost
every
real
world
data
model.
</dd>
<dt>
Terseness
</dt>
<dd>
The
JSON-LD
syntax
must
be
very
terse
and
human
readable,
requiring
as
little
effort
as
possible
from
the
developer.
</dd>
<dt>
Zero
Edits,
most
of
the
time
</dt>
<dd>
JSON-LD
must
make
the
transition
to
JSON-LD
as
simple
as
possible.
In
many
cases,
zero
edits
to
the
JSON
document
and
the
addition
of
one
line
to
the
HTTP
response
should
suffice
(see
<a href="#referencing-contexts-from-json-documents">
</a>
).
This
allows
organizations
that
have
already
deployed
large
JSON-based
infrastructure
to
use
JSON-LD's
features
in
a
way
that
is
not
disruptive
to
their
day-to-day
operations
and
is
transparent
to
their
current
customers.
However,
there
are
times
where
mapping
JSON
to
a
graph
representation
is
more
complex
than
a
simple
one-line
change.
In
these
instances,
rather
than
extending
JSON-LD
to
support
an
esoteric
use
case,
we
chose
not
to
support
the
use
case.
While
Zero
Edits
is
a
design
goal,
it
is
not
always
possible
without
adding
great
complexity
to
the
language.
We
should
focus
on
simplicity
when
possible.
</dd>
</dl>
</section>
<section id="terminology" class="normative">
<h2>
<span class="secno">
3.
</span>
Terminology
</h2>
<section id="general-terminology">
<h3>
<span class="secno">
3.1
</span>
General
Terminology
</h3>
<p>
This
document
uses
the
following
terms
as
defined
in
JSON
[
<cite>
<a href="#bib-RFC4627" class="bibref">
RFC4627
</a>
</cite>
].
Refer
to
the
<em>
JSON
Grammar
</em>
section
in
[
<cite>
<a href="#bib-RFC4627" class="bibref">
RFC4627
</a>
</cite>
]
for
formal
definitions.
</p>
<dl>
<dt>
<dfn id="dfn-json-object" title="json-object">
JSON
object
</dfn>
</dt>
<dd>
An
object
structure
is
represented
as
a
pair
of
curly
brackets
surrounding
zero
or
more
key-value
pairs.
A
key
is
a
<a href="#dfn-string" title="string" class="tref internalDFN">
string
</a>.
A
single
colon
comes
after
each
key,
separating
the
key
from
the
value.
A
single
comma
separates
a
value
from
a
following
key.
</dd>
<dt>
<dfn id="dfn-array" title="array">
array
</dfn>
</dt>
<dd>
An
array
structure
is
represented
as
square
brackets
surrounding
zero
or
more
values.
Values
are
separated
by
commas.
In
JSON,
an
array
is
an
<em>
ordered
</em>
sequence
of
zero
or
more
values.
While
JSON-LD
uses
the
same
array
representation
as
JSON,
the
collection
is
<em>
unordered
</em>
by
default.
While
order
is
preserved
in
regular
JSON
arrays,
it
is
not
in
regular
JSON-LD
arrays
unless
specific
markup
is
provided
(see
<a class="sec-ref" href="#sets-and-lists">
<span class="secno">
<del class="diff-old">6.9
</del>
<ins class="diff-chg">6.10
</ins>
</span>
<span class="sec-title">
Sets
and
Lists
</span>
</a>
).
</dd>
<dt>
<dfn id="dfn-string" title="string">
string
</dfn>
</dt>
<dd>
A
string
is
a
sequence
of
zero
or
more
Unicode
characters,
wrapped
in
double
quotes,
using
backslash
escapes
(if
necessary).
A
character
is
represented
as
a
single
character
string.
</dd>
<dt>
<dfn id="dfn-number" title="number">
number
</dfn>
</dt>
<dd>
A
number
is
similar
to
that
used
in
most
programming
languages,
except
that
the
octal
and
hexadecimal
formats
are
not
used
and
that
leading
zeros
are
not
allowed.
</dd>
<dt>
<dfn id="dfn-true" title="true">
true
</dfn>
and
<dfn id="dfn-false" title="false">
false
</dfn>
</dt>
<dd>
Values
that
are
used
to
express
one
of
two
possible
boolean
states.
</dd>
<dt>
<dfn id="dfn-null" title="null">
null
</dfn>
</dt>
<dd>
The
<a href="#dfn-null" title="null" class="tref internalDFN">
null
</a>
value,
which
is
typically
used
to
clear
or
forget
data.
For
example,
A
key-value
pair
in
the
<code>
@context
</code>
where
the
value
is
<a href="#dfn-null" title="null" class="tref internalDFN">
null
</a>
explicitly
decouples
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
's
association
with
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
A
key-value
pair
in
the
body
of
a
JSON-LD
document
whose
value
is
<a href="#dfn-null" title="null" class="tref internalDFN">
null
</a>
has
the
same
meaning
as
if
the
key-value
pair
was
not
defined.
If
<code>
@value
</code>,
<code>
@list
</code>,
or
<code>
@set
</code>
is
set
to
<a href="#dfn-null" title="null" class="tref internalDFN">
null
</a>
in
expanded
form,
then
the
entire
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
object
</a>
is
ignored.
</dd>
</dl>
</section>
<section id="syntax-tokens-and-keywords">
<h3>
<span class="secno">
3.2
</span>
Syntax
Tokens
and
Keywords
</h3>
<p>
JSON-LD
specifies
a
number
of
syntax
tokens
and
<dfn id="dfn-keyword" title="keyword">
keywords
</dfn>
that
are
a
core
part
of
the
language:
</p>
<dl>
<dt>
<code>
@context
</code>
</dt>
<dd>
Used
to
define
the
short-hand
names
that
are
used
throughout
a
JSON-LD
document.
These
short-hand
names
are
called
<a href="#dfn-term" title="term" class="tref internalDFN">
terms
</a>
and
help
developers
to
express
specific
identifiers
in
a
compact
manner.
The
<code>
@context
</code>
keyword
is
described
in
detail
in
the
section
titled
<a class="sec-ref" href="#the-context">
<span class="secno">
5.1
</span>
<span class="sec-title">
The
Context
</span>
</a>.
</dd>
<dt>
<code>
@id
</code>
</dt>
<dd>
Used
to
uniquely
identify
<em>
things
</em>
that
are
being
described
in
the
document.
This
keyword
is
described
in
<a class="sec-ref" href="#node-identifiers">
<span class="secno">
5.3
</span>
<span class="sec-title">
Node
Identifiers
</span>
</a>.
</dd>
<dt>
<code>
@value
</code>
</dt>
<dd>
Used
to
specify
the
data
that
is
associated
with
a
particular
<a href="#dfn-property" title="property" class="tref internalDFN">
property
</a>
in
the
graph.
This
keyword
is
described
in
<a class="sec-ref" href="#string-internationalization">
<span class="secno">
<del class="diff-old">6.5
</del>
<ins class="diff-chg">6.6
</ins>
</span>
<span class="sec-title">
String
Internationalization
</span>
</a>
and
<a class="sec-ref" href="#typed-values">
<span class="secno">
6.2
</span>
<span class="sec-title">
Typed
Values
</span>
</a>.
</dd>
<dt>
<code>
@language
</code>
</dt>
<dd>
Used
to
specify
the
native
language
for
a
particular
value
or
the
default
language
of
a
JSON-LD
document.
This
keyword
is
described
in
the
section
titled
<a class="sec-ref" href="#string-internationalization">
<span class="secno">
<del class="diff-old">6.5
</del>
<ins class="diff-chg">6.6
</ins>
</span>
<span class="sec-title">
String
Internationalization
</span>
</a>.
</dd>
<dt>
<code>
@type
</code>
</dt>
<dd>
Used
to
set
the
data
type
of
a
<a href="#dfn-node" title="node" class="tref internalDFN">
node
</a>
or
<a href="#dfn-typed-value" title="typed-value" class="tref internalDFN">
typed
value
</a>.
This
keyword
is
described
in
the
section
titled
<a class="sec-ref" href="#typed-values">
<span class="secno">
6.2
</span>
<span class="sec-title">
Typed
Values
</span>
</a>.
</dd>
<dt>
<code>
@container
</code>
</dt>
<dd>
Used
to
set
the
default
container
type
for
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>.
This
keyword
is
described
in
the
section
titled
<a class="sec-ref" href="#sets-and-lists">
<span class="secno">
<del class="diff-old">6.9
</del>
<ins class="diff-chg">6.10
</ins>
</span>
<span class="sec-title">
Sets
and
Lists
</span>
</a>.
</dd>
<dt>
<code>
@list
</code>
</dt>
<dd>
Used
to
express
an
ordered
set
of
data.
This
keyword
is
described
in
the
section
titled
<a class="sec-ref" href="#sets-and-lists">
<span class="secno">
<del class="diff-old">6.9
</del>
<ins class="diff-chg">6.10
</ins>
</span>
<span class="sec-title">
Sets
and
Lists
</span>
</a>.
</dd>
<dt>
<code>
@set
</code>
</dt>
<dd>
Used
to
express
an
unordered
set
of
data
and
to
ensure
that
values
are
always
represented
as
arrays.
This
keyword
is
described
in
the
section
titled
<a class="sec-ref" href="#sets-and-lists">
<span class="secno">
<del class="diff-old">6.9
</del>
<ins class="diff-chg">6.10
</ins>
</span>
<span class="sec-title">
Sets
and
Lists
</span>
</a>.
</dd>
<dt>
<code>
@index
</code>
</dt>
<dd>
Used
to
specify
that
a
container
is
used
to
index
information
and
that
processing
should
continue
deeper
into
a
JSON
data
structure.
This
keyword
is
described
in
the
section
titled
<a class="sec-ref" href="#data-indexing">
<span class="secno">
<del class="diff-old">6.16
</del>
<ins class="diff-chg">6.17
</ins>
</span>
<span class="sec-title">
Data
Indexing
</span>
</a>.
</dd>
<dt>
<code>
@vocab
</code>
</dt>
<dd>
Used
to
expand
properties
and
values
in
<code>
@type
</code>
with
a
common
prefix
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
This
keyword
is
described
in
section
<a class="sec-ref" href="#iris">
<span class="secno">
5.2
</span>
<span class="sec-title">
IRIs
</span>
</a>.
</dd>
<dt>
<code>
@graph
</code>
</dt>
<dd>
Used
to
explicitly
label
a
<a href="#dfn-json-ld-graph" title="json-ld-graph" class="tref internalDFN">
JSON-LD
graph
</a>.
This
keyword
is
described
in
<a class="sec-ref" href="#named-graphs">
<span class="secno">
<del class="diff-old">6.11
</del>
<ins class="diff-chg">6.12
</ins>
</span>
<span class="sec-title">
Named
Graphs
</span>
</a>.
</dd>
<dt>
<code>:
</code>
</dt>
<dd>
The
separator
for
JSON
keys
and
values
that
use
<a href="#dfn-compact-iri" title="compact-iri" class="tref internalDFN">
compact
IRIs
</a>.
</dd>
</dl>
<p>
For
the
avoidance
of
doubt,
all
keys,
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keywords
</a>,
and
values
in
JSON-LD
are
case-sensitive.
</p>
</section>
</section>
<section id="conformance" class="normative">
<h2>
<span class="secno">
4.
</span>
Conformance
</h2>
<p>
This
specification
describes
the
conformance
criteria
for
JSON-LD
documents.
This
criteria
is
relevant
to
authors
and
authoring
tool
implementers.
</p>
<p>
A
<a href="#dfn-json-ld-document" title="json-ld-document" class="tref internalDFN">
JSON-LD
document
</a>
complies
with
this
specification
if
it
follows
the
normative
statements
in
section
<a class="sec-ref" href="#json-ld-grammar">
<span class="secno">
B.
</span>
<span class="sec-title">
JSON-LD
Grammar
</span>
</a>.
JSON
documents
can
be
interpreted
as
JSON-LD
by
following
the
normative
statements
in
section
<a href="#referencing-contexts-from-json-documents">
</a>.
For
convenience,
normative
statements
for
documents
are
often
phrased
as
statements
on
the
properties
of
the
document.
</p>
<p>
The
key
words
<em title="must" class="rfc2119">
must
</em>,
<em title="must not" class="rfc2119">
must
not
</em>,
<em title="required" class="rfc2119">
required
</em>,
<em title="shall" class="rfc2119">
shall
</em>,
<em title="shall not" class="rfc2119">
shall
not
</em>,
<em title="should" class="rfc2119">
should
</em>,
<em title="should not" class="rfc2119">
should
not
</em>,
<em title="recommended" class="rfc2119">
recommended
</em>,
<em title="not recommended" class="rfc2119">
not
recommended
</em>,
<em title="may" class="rfc2119">
may
</em>,
and
<em title="optional" class="rfc2119">
optional
</em>
in
this
specification
have
the
meaning
defined
in
[
<cite>
<a href="#bib-RFC2119" class="bibref">
RFC2119
</a>
</cite>
].
</p>
</section>
<section id="basic-concepts" class="normative">
<h2>
<span class="secno">
5.
</span>
Basic
Concepts
</h2>
<p>
JSON
[
<cite>
<a href="#bib-RFC4627" class="bibref">
RFC4627
</a>
</cite>
]
is
a
lightweight,
language-independent
data-interchange
format.
It
is
easy
to
parse
and
easy
to
generate.
However,
it
is
difficult
to
integrate
JSON
from
different
sources
as
the
data
has
just
local
meaning.
Furthermore,
JSON
has
no
built-in
support
for
hyperlinks
-
a
fundamental
building
block
on
the
Web.
Let's
look
at
an
example
that
we
will
be
using
for
the
rest
of
this
section:
</p>
<del class="diff-old">  {
  "name": "Manu Sporny",
  "homepage": "http://manu.sporny.org/",
  "image": "http://manu.sporny.org/images/manu.png"
</del>
  <div class="example"><div class="example-title"><span>Example 1</span>: Sample JSON document</div><pre class="example">{
<ins class="diff-chg">  "name": "Manu Sporny",
  "homepage": "http://manu.sporny.org/",
  "image": "http://manu.sporny.org/images/manu.png"
</ins>
}
</pre>
</div>
<p>
It's
obvious
for
humans
that
the
data
is
about
a
person
whose
name
is
"Manu
Sporny"
and
that
the
<code>
homepage
</code>
property
contains
the
URL
of
that
person's
homepage.
A
machine
doesn't
have
such
an
intuitive
understanding
and
sometimes,
even
for
humans,
it
is
difficult
to
resolve
ambiguities
in
such
representations.
This
problem
can
be
solved
by
using
unambiguous
identifiers
to
denote
the
different
concepts
instead
of
<a href="#dfn-term" title="term" class="tref internalDFN">
terms
</a>
such
as
"name",
"homepage",
etc.
</p>
<p>
<a href="#dfn-linked-data" title="linked-data" class="tref internalDFN">
Linked
Data
</a>,
and
the
Web
in
general,
uses
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>
(Internationalized
Resource
Identifiers
as
described
in
[
<cite>
<a href="#bib-RFC3987" class="bibref">
RFC3987
</a>
</cite>
])
for
unambiguous
identification.
The
idea
is
to
assign
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>
to
something
that
may
be
of
use
to
other
developers
and
that
it
is
useful
to
give
them
an
unambiguous
identifier.
That
is,
it
is
useful
for
<a href="#dfn-term" title="term" class="tref internalDFN">
terms
</a>
to
expand
to
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>
so
that
developers
don't
accidentally
step
on
each
other's
terms.
Furthermore,
developers
and
machines
are
able
to
use
this
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
(by
using
a
web
browser,
for
instance)
to
go
to
the
term
and
get
a
definition
of
what
the
term
means.
</p>
<p>
Leveraging
the
well-known
<a href="http://schema.org/">
schema.org
vocabulary
</a>,
the
example
above
could
be
unambiguously
expressed
as
follows:
</p>
<del class="diff-old">  {
  "": "Manu Sporny",
  ",
  "
</del>
  <div class="example"><div class="example-title"><span>Example 2</span>: Sample JSON-LD document using full IRIs instead of terms</div><pre class="example">{
<ins class="diff-chg">  "<span class="diff">http://schema.org/name</span>": "Manu Sporny",
  "<span class="diff">http://schema.org/url</span>": <span class="diff">{ "@id": </span>"http://manu.sporny.org/" <span class="diff">}</span>,
  "<span class="diff">http://schema.org/image</span>": <span class="diff">{ "@id": </span>"http://manu.sporny.org/images/manu.png" <span class="diff">}</span>
</ins>
}
</pre>
</div>
<p>
In
the
example
above,
every
property
is
unambiguously
identified
by
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
and
all
values
representing
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>
are
explicitly
marked
as
such
by
the
<code>
@id
</code>
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keyword
</a>.
While
this
is
a
valid
JSON-LD
document
that
is
very
specific
about
its
data,
the
document
is
also
overly
verbose
and
difficult
to
work
with
for
human
developers.
To
address
this
issue,
JSON-LD
introduces
the
notion
of
a
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
as
described
in
the
next
section.
</p>
<section id="the-context">
<h3>
<span class="secno">
5.1
</span>
The
Context
</h3>
<p>
Simply
speaking,
a
<dfn id="dfn-context" title="context">
context
</dfn>
is
used
to
map
<a href="#dfn-term" title="term" class="tref internalDFN">
terms
</a>,
i.e.,
<a href="#dfn-property" title="property" class="tref internalDFN">
properties
</a>
with
associated
values,
to
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>.
<a href="#dfn-term" title="term" class="tref internalDFN">
Terms
</a>
are
case
sensitive
and
any
valid
<a href="#dfn-string" title="string" class="tref internalDFN">
string
</a>
that
is
not
a
reserved
JSON-LD
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keyword
</a>
can
be
used
as
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>.
</p>
<p>
For
the
sample
document
in
the
previous
section,
a
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
would
look
something
like
this:
</p>
<del class="diff-old">    {
  "@context":
  {
    "name": "http://schema.org/name",
    "image": {
      "@id": "http://schema.org/image",
      "@type": "@id"
    },
    "homepage": {
      "@id": "http://schema.org/url",
      "@type": "@id"
    }
  }
</del>
    <div class="example"><div class="example-title"><span>Example 3</span>: Context for the sample document in the previous section</div><pre class="example">{
  <span class="diff">"@context":
<ins class="diff-chg">  {
    "name": "http://schema.org/name",
    "image": {
      "@id": "http://schema.org/image",
      "@type": "@id"
    },
    "homepage": {
      "@id": "http://schema.org/url",
      "@type": "@id"
    }
  }</span>
</ins>
}
</pre>
</div>
<p>
As
the
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
above
shows,
the
value
of
a
<dfn id="dfn-term-definition" title="term-definition">
term
definition
</dfn>
can
either
be
a
simple
string,
mapping
the
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
to
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
or
a
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
object
</a>.
</p>
<p>
When
a
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
object
</a>
is
associated
with
a
term,
it
is
called
an
<a href="#dfn-expanded-term-definition" title="expanded-term-definition" class="tref internalDFN">
expanded
term
definition
</a>.
<dfn id="dfn-expanded-term-definition" title="expanded-term-definition">
Expanded
term
definitions
</dfn>
may
be
used
to
associate
<a href="#type-coercion">
type
</a>
or
<a href="#string-internationalization">
language
information
</a>
with
a
term.
The
example
above
specifies
that
the
values
of
<code>
image
</code>
and
<code>
homepage
</code>
terms
are
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>.
They
also
allow
terms
to
be
used
for
<a href="#data-indexing">
index
maps
</a>
and
to
specify
whether
<a href="#dfn-array" title="array" class="tref internalDFN">
array
</a>
values
are
to
be
interpreted
as
<a href="#sets-and-lists">
sets
or
lists
</a>.
<a href="#dfn-expanded-term-definition" title="expanded-term-definition" class="tref internalDFN">
Expanded
term
definitions
</a>
may
be
defined
using
<a href="#dfn-absolute-iri" title="absolute-iri" class="tref internalDFN">
absolute
</a>
or
<a href="#dfn-compact-iri" title="compact-iri" class="tref internalDFN">
compact
IRIs
</a>
as
keys,
which
is
mainly
used
to
associate
type
or
language
information
with
an
<a href="#dfn-absolute-iri" title="absolute-iri" class="tref internalDFN">
absolute
</a>
or
<a href="#dfn-compact-iri" title="compact-iri" class="tref internalDFN">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
</p>
<p>
<a href="#dfn-context" title="context" class="tref internalDFN">
Contexts
</a>
can
either
be
directly
embedded
into
the
document
or
be
referenced.
Assuming
the
context
document
in
the
previous
example
can
be
retrieved
at
<code>
http://json-ld.org/contexts/person.jsonld
</code>,
it
can
be
referenced
by
adding
a
single
line
and
allows
a
JSON-LD
document
to
be
expressed
much
more
concisely
as
shown
in
the
example
below:
</p>
<del class="diff-old">    {

  "name": "Manu Sporny",
  "homepage": "http://manu.sporny.org/",
  "image": "http://manu.sporny.org/images/manu.png"
</del>
    <div class="example"><div class="example-title"><span>Example 4</span>: Referencing a JSON-LD context</div><pre class="example">{
  <span class="diff">"@context": "http://json-ld.org/contexts/person.jsonld",</span>
<ins class="diff-chg">  "name": "Manu Sporny",
  "homepage": "http://manu.sporny.org/",
  "image": "http://manu.sporny.org/images/manu.png"
</ins>
}
</pre>
</div>
<p>
The
referenced
context
not
only
specifies
how
the
terms
map
to
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>
in
the
Schema.org
vocabulary
but
also
specifies
that
the
values
of
the
<code>
homepage
</code>
and
<code>
image
</code>
property
can
be
interpreted
as
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
<del class="diff-old">(e.g.
</del>
<ins class="diff-chg">(
</ins>
<code>
"@type":
"@id"
</code>,
see
section
<a class="sec-ref" href="#iris">
<span class="secno">
5.2
</span>
<span class="sec-title">
IRIs
</span>
</a>
for
more
details).
This
information
gives
the
data
global
context
and
allows
developers
to
re-use
each
other's
data
without
having
to
agree
to
how
their
data
will
interoperate
on
a
site-by-site
basis.
External
JSON-LD
context
documents
may
contain
extra
information
located
outside
of
the
<code>
@context
</code>
key,
such
as
documentation
about
the
<a href="#dfn-term" title="term" class="tref internalDFN">
terms
</a>
declared
in
the
document.
Information
contained
outside
of
the
<code>
@context
</code>
value
is
ignored
when
the
document
is
used
as
an
external
JSON-LD
context
document.
</p>
<p>
Contexts
may
also
be
specified
in-line.
This
has
the
advantage
that
<a href="#dfn-json-ld-document" title="json-ld-document" class="tref internalDFN">
JSON-LD
documents
</a>
can
be
processed
even
in
the
absence
of
a
connection
to
the
Web.
</p>
<del class="diff-old">    {
  "@context":
  {
    "name": "http://schema.org/name",
    "image": {
      "@id": "http://schema.org/image",
      "@type": "@id"
    },
    "homepage": {
      "@id": "http://schema.org/url",
      "@type": "@id"
    }
  },
  "name": "Manu Sporny",
  "homepage": "http://manu.sporny.org/",
  "image": "http://manu.sporny.org/images/manu.png"
</del>
    <div class="example"><div class="example-title"><span>Example 5</span>: In-line context definition</div><pre class="example">{
  <span class="diff">"@context":
<ins class="diff-chg">  {
    "name": "http://schema.org/name",
    "image": {
      "@id": "http://schema.org/image",
      "@type": "@id"
    },
    "homepage": {
      "@id": "http://schema.org/url",
      "@type": "@id"
    }
  },</span>
  "name": "Manu Sporny",
  "homepage": "http://manu.sporny.org/",
  "image": "http://manu.sporny.org/images/manu.png"
</ins>
}
</pre>
</div>
</section>
<section id="iris">
<h3>
<span class="secno">
5.2
</span>
IRIs
</h3>
<p>
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>
(Internationalized
Resource
Identifiers
[
<cite>
<a href="#bib-RFC3987" class="bibref">
RFC3987
</a>
</cite>
])
are
fundamental
to
<a href="#dfn-linked-data" title="linked-data" class="tref internalDFN">
Linked
Data
</a>
as
that
is
how
most
<a href="#dfn-node" title="node" class="tref internalDFN">
nodes
</a>
and
<a href="#dfn-property" title="property" class="tref internalDFN">
properties
</a>
are
identified.
In
JSON-LD,
IRIs
may
be
represented
as
an
<a href="#dfn-absolute-iri" title="absolute-iri" class="tref internalDFN">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
or
a
<a href="#dfn-relative-iri" title="relative-iri" class="tref internalDFN">
relative
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
An
<dfn id="dfn-absolute-iri" title="absolute-iri">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</dfn>
is
defined
in
[
<cite>
<a href="#bib-RFC3987" class="bibref">
RFC3987
</a>
</cite>
]
as
containing
a
<em>
scheme
</em>
along
with
<em>
path
</em>
and
optional
<em>
query
</em>
and
<em>
fragment
</em>
segments.
A
<dfn id="dfn-relative-iri" title="relative-iri">
relative
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</dfn>
is
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
that
is
relative
to
some
other
<a href="#dfn-absolute-iri" title="absolute-iri" class="tref internalDFN">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
In
JSON-LD
all
<a href="#dfn-relative-iri" title="relative-iri" class="tref internalDFN">
relative
IRIs
</a>
are
resolved
relative
to
the
<dfn id="dfn-base-iri" title="base-iri">
base
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</dfn>
associated
with
the
document,
which
is
typically
the
directory
path
containing
the
document.
</p>
<p>
<a href="#dfn-absolute-iri" title="absolute-iri" class="tref internalDFN">
IRIs
</a>
can
be
expressed
directly
in
the
key
position
like
so:
</p>
<del class="diff-old">  {
...
  "": "Manu Sporny",
...
</del>
  <div class="example"><div class="example-title"><span>Example 6</span>: IRI as a key</div><pre class="example">{
<ins class="diff-chg">...
  "<span class="diff">http://schema.org/name</span>": "Manu Sporny",
...
</ins>
}
</pre>
</div>
<p>
In
the
example
above,
the
key
<code>
http://schema.org/name
</code>
is
interpreted
as
an
<a href="#dfn-absolute-iri" title="absolute-iri" class="tref internalDFN">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
because
it
contains
a
colon
(
<code>:
</code>
)
and
the
"http"
<a href="#dfn-prefix" title="prefix" class="tref internalDFN">
prefix
</a>
does
not
exist
in
the
context.
</p>
<p>
Term-to-
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
expansion
occurs
if
the
key
matches
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
defined
within
the
<a href="#dfn-active-context" title="active-context" class="tref internalDFN">
active
context
</a>:
</p>
<del class="diff-old">  {
  "":
  {
    ""
...
  },
  "": "Manu Sporny",
  "status": "trollin'",
...
</del>
  <div class="example"><div class="example-title"><span>Example 7</span>: Term expansion from context definition</div><pre class="example">{
<ins class="diff-chg">  "<span class="diff">@context</span>":
  {
    "<span class="diff">name</span>": "<span class="diff">http://schema.org/name</span>"
...
  },
  "<span class="diff">name</span>": "Manu Sporny",
  "status": "trollin'",
...
</ins>
}
</pre>
</div>
<p>
JSON
keys
that
do
not
expand
to
an
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
are
ignored,
or
removed
in
some
cases,
by
the
[
<cite>
<a href="#bib-JSON-LD-API" class="bibref">
JSON-LD-API
</a>
</cite>
].
However,
JSON
keys
that
do
not
include
a
mapping
in
the
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
are
still
considered
valid
expressions
in
JSON-LD
documents—the
keys
just
don't
expand
to
unambiguous
identifiers.
</p>
<p>
At
times,
all
properties
and
types
may
come
from
the
same
vocabulary.
JSON-LD's
<code>
@vocab
</code>
keyword
allows
an
author
to
set
a
common
prefix
to
be
used
for
all
properties
and
types
that
do
not
match
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
or
are
neither
a
<a href="#dfn-compact-iri" title="compact-iri" class="tref internalDFN">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
nor
an
<a href="#dfn-absolute-iri" title="absolute-iri" class="tref internalDFN">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
(i.e.,
they
do
not
contain
a
colon).
</p>
<del class="diff-old">  {
  "@context": {
    "@vocab": "http://schema.org/"
  },
  "@type": ,
  : "Manu Sporny",
</del>
  <div class="example"><div class="example-title"><span>Example 8</span>: Using a common vocabulary prefix</div><pre class="example">{
  <span class="diff">"@context": {
<ins class="diff-chg">    "@vocab": "http://schema.org/"
  },</span>
  "@type": <span class="diff">"Person"</span>,
</ins>  <span class="diff">"name"</span>: "Manu Sporny",
}
</pre>
</div>
<p>
An
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
is
generated
when
a
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
object
</a>
is
used
in
the
value
position
and
contains
an
<code>
@id
</code>
keyword:
</p>
<del class="diff-old">  {
...
  "homepage": { "": "http://manu.sporny.org" }
...
</del>
  <div class="example"><div class="example-title"><span>Example 9</span>: Expanded IRI definition</div><pre class="example">{
<ins class="diff-chg">...
  "homepage": { "<span class="diff">@id</span>": "http://manu.sporny.org" }
...
</ins>
}
</pre>
</div>
<p>
Specifying
a
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
object
</a>
with
an
<code>
@id
</code>
key
is
used
to
identify
that
<a href="#dfn-node" title="node" class="tref internalDFN">
node
</a>
using
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
This
facility
may
also
be
used
to
link
to
another
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
object
</a>
using
a
mechanism
called
<a href="#dfn-embedding" title="embedding" class="tref internalDFN">
embedding
</a>,
which
is
covered
in
the
section
titled
<a class="sec-ref" href="#embedding">
<span class="secno">
<del class="diff-old">6.10
</del>
<ins class="diff-chg">6.11
</ins>
</span>
<span class="sec-title">
Embedding
</span>
</a>.
</p>
<p>
If
type
<a href="#dfn-coercion" title="coercion" class="tref internalDFN">
coercion
</a>
rules
are
specified
in
the
<code>
@context
</code>
for
a
particular
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
or
property
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>,
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
is
generated:
</p>
<del class="diff-old">
  "@context":
  {
    ...
    "homepage":
    {
      "@id": "http://schema.org/homepage",
      "@type": "@id"
    }
    ...
  }
...
  "homepage": "http://manu.sporny.org/",
...
</del>
  <div class="example"><div class="example-title"><span>Example 10</span>: Type coercion</div><pre class="example">{<span class="diff">
<ins class="diff-chg">  "@context":
  {
    ...
    "homepage":
    {
      "@id": "http://schema.org/homepage",
      "@type": "@id"
    }
    ...
  }</span>
...
  "homepage": "http://manu.sporny.org/",
...
</ins>
}
</pre>
</div>
<p>
In
the
example
above,
even
though
the
value
<code>
http://manu.sporny.org/
</code>
is
expressed
as
a
JSON
<a href="#dfn-string" title="string" class="tref internalDFN">
string
</a>,
the
type
<a href="#dfn-coercion" title="coercion" class="tref internalDFN">
coercion
</a>
rules
will
transform
the
value
into
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
when
generating
the
<a href="#dfn-json-ld-graph" title="json-ld-graph" class="tref internalDFN">
JSON-LD
graph
</a>.
See
<a class="sec-ref" href="#type-coercion">
<span class="secno">
6.3
</span>
<span class="sec-title">
Type
Coercion
</span>
</a>
for
more
details
about
this
feature.
</p>
<p>
In
summary,
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>
can
be
expressed
in
a
variety
of
different
ways
in
JSON-LD:
</p>
<ol>
<li>
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
object
</a>
keys
that
have
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
mapping
in
the
<a href="#dfn-active-context" title="active-context" class="tref internalDFN">
active
context
</a>
expand
to
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
(only
applies
outside
of
the
<a href="#dfn-context-definition" title="context-definition" class="tref internalDFN">
context
definition
</a>
).
</li>
<li>
If
there
is
a
<code>
@vocab
</code>
mapping
in
the
active
context,
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
object
</a>
keys
without
an
explicit
mapping
in
the
<a href="#dfn-active-context" title="active-context" class="tref internalDFN">
active
context
</a>
are
expanded
to
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
</li>
<li>
An
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
is
generated
for
the
<a href="#dfn-string" title="string" class="tref internalDFN">
string
</a>
value
specified
using
<code>
@id
</code>
or
<code>
@type
</code>.
</li>
<li>
An
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
is
generated
for
the
<a href="#dfn-string" title="string" class="tref internalDFN">
string
</a>
value
of
any
key
for
which
there
are
<a href="#dfn-coercion" title="coercion" class="tref internalDFN">
coercion
</a>
rules
that
contain
a
<code>
@type
</code>
key
that
is
set
to
a
value
of
<code>
@id
</code>
<ins class="diff-new">or
</ins><code><ins class="diff-new">
@vocab
</ins>
</code>.
</li>
</ol>
</section>
<section id="node-identifiers">
<h3>
<span class="secno">
5.3
</span>
Node
Identifiers
</h3>
<p>
To
be
able
to
externally
reference
<a href="#dfn-node" title="node" class="tref internalDFN">
nodes
</a>
in
a
<a href="#dfn-json-ld-graph" title="json-ld-graph" class="tref internalDFN">
graph
</a>,
it
is
important
that
each
<a href="#dfn-node" title="node" class="tref internalDFN">
node
</a>
<del class="diff-old">have
</del>
<ins class="diff-chg">has
</ins>
an
unambiguous
identifier.
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>
are
a
fundamental
concept
of
<a href="#dfn-linked-data" title="linked-data" class="tref internalDFN">
Linked
Data
</a>,
and
<a href="#dfn-node" title="node" class="tref internalDFN">
nodes
</a>
should
have
a
de-referenceable
identifier
used
to
name
and
locate
them.
For
<a href="#dfn-node" title="node" class="tref internalDFN">
nodes
</a>
to
be
truly
linked,
de-referencing
the
identifier
should
result
in
a
representation
of
that
<a href="#dfn-node" title="node" class="tref internalDFN">
node
</a>.
Associating
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
with
a
<a href="#dfn-node" title="node" class="tref internalDFN">
node
</a>
tells
an
application
that
it
can
fetch
the
resource
associated
with
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
and
get
back
a
description
of
the
<a href="#dfn-node" title="node" class="tref internalDFN">
node
</a>.
</p>
<p>
<a href="#dfn-json-ld-document" title="json-ld-document" class="tref internalDFN">
JSON-LD
documents
</a>
may
also
contain
descriptions
of
other
<a href="#dfn-node" title="node" class="tref internalDFN">
nodes
</a>,
so
it
is
necessary
to
be
able
to
uniquely
identify
each
<a href="#dfn-node" title="node" class="tref internalDFN">
node
</a>
so
that
the
data
is
associated
with
the
correct
<a href="#dfn-node" title="node" class="tref internalDFN">
node
</a>
in
an
unambiguous
way.
</p>
<p>
A
<a href="#dfn-node" title="node" class="tref internalDFN">
node
</a>
is
identified
using
the
<code>
@id
</code>
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keyword
</a>:
</p>
<del class="diff-old">  {
  "@context":
  {
    ...
    "homepage":
    {
      "@id": "http://schema.org/homepage",
      "@type": "@id"
    }
  },
  "",
  "homepage": "http://joebob.example.com/",
  ...
</del>
  <div class="example"><div class="example-title"><span>Example 11</span>: Identifying a node</div><pre class="example">{
<ins class="diff-chg">  "@context":
  {
    ...
    "homepage":
    {
      "@id": "http://schema.org/homepage",
      "@type": "@id"
    }
  },
  "<span class="diff">@id</span>": "<span class="diff">http://example.org/people#joebob</span>",
  "homepage": "http://joebob.example.com/",
  ...
</ins>
}
</pre>
</div>
<p>
The
example
above
contains
a
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
object
</a>
identified
by
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
<code>
http://example.org/people#joebob
</code>.
</p>
</section>
<section id="specifying-the-type">
<h3>
<span class="secno">
5.4
</span>
Specifying
the
Type
</h3>
<p>
The
type
of
a
particular
node
can
be
specified
using
the
<code>
@type
</code>
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keyword
</a>.
In
<a href="#dfn-linked-data" title="linked-data" class="tref internalDFN">
Linked
Data
</a>,
types
are
uniquely
identified
with
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
</p>
<del class="diff-old">{
...
  "@id": "http://example.org/places#BrewEats",
  "",
...
</del>
<div class="example"><div class="example-title"><span>Example 12</span>: Specifying the type for a node</div><pre class="example">{
<ins class="diff-chg">...
  "@id": "http://example.org/places#BrewEats",
  "<span class="diff">@type</span>": "<span class="diff">http://schema.org/Restaurant</span>",
...
</ins>
}
</pre>
</div>
<p>
A
node
can
be
assigned
more
than
one
type
by
using
an
<a href="#dfn-array" title="array" class="tref internalDFN">
array
</a>:
</p>
<del class="diff-old">{
...
  "@id": "http://example.org/places#BrewEats",
  "
...
</del>
<div class="example"><div class="example-title"><span>Example 13</span>: Specifying multiple types for a node</div><pre class="example">{
<ins class="diff-chg">...
  "@id": "http://example.org/places#BrewEats",
  "<span class="diff">@type</span>": <span class="diff">[ "http://schema.org/Restaurant", "http://schema.org/Brewery" ],</span>
...
</ins>
}
</pre>
</div>
<p>
The
value
of
a
<code>
@type
</code>
key
may
also
be
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
defined
in
the
<a href="#dfn-active-context" title="active-context" class="tref internalDFN">
active
context
</a>:
</p>
<del class="diff-old">{
  "@context": {
    ...


  }
  "@id": "http://example.org/places#BrewEats",
  ,
  ...
</del>
<div class="example"><div class="example-title"><span>Example 14</span>: Using a term to specify the type</div><pre class="example">{
<ins class="diff-chg">  "@context": {
    ...
</ins>    <span class="diff">"Restaurant": "http://schema.org/Restaurant", </span>
    <span class="diff">"Brewery": "http://schema.org/Brewery"</span>
<ins class="diff-chg">
  }
  "@id": "http://example.org/places#BrewEats",
</ins>  <span class="diff">"@type": ["Restaurant", "Brewery"]</span>,
<ins class="diff-chg">
  ...
</ins>
}
</pre>
</div>
</section>
</section>
<section id="advanced-concepts">
<h2>
<span class="secno">
6.
</span>
Advanced
Concepts
</h2>
<em>
This
section
is
normative.
</em>
<p>
JSON-LD
has
a
number
of
features
that
provide
functionality
above
and
beyond
the
core
functionality
described
above.
The
following
section
describes
this
advanced
functionality
in
more
detail.
</p>
<section id="compact-iris">
<h3>
<span class="secno">
6.1
</span>
Compact
IRIs
</h3>
<p>
A
document
on
the
Web
that
defines
one
or
more
IRIs
for
use
as
<a href="#dfn-property" title="property" class="tref internalDFN">
properties
</a>
in
Linked
Data
is
called
a
<dfn id="dfn-vocabulary" title="vocabulary">
vocabulary
</dfn>.
<a href="#dfn-term" title="term" class="tref internalDFN">
Terms
</a>
in
<a href="#dfn-linked-data" title="linked-data" class="tref internalDFN">
Linked
Data
</a>
documents
may
draw
from
a
number
of
different
<a href="#dfn-vocabulary" title="vocabulary" class="tref internalDFN">
vocabularies
</a>
s.
At
times,
declaring
every
single
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
that
a
document
uses
can
require
the
developer
to
declare
tens,
if
not
hundreds
of
potential
vocabulary
<a href="#dfn-term" title="term" class="tref internalDFN">
terms
</a>
that
are
used
across
an
application.
This
is
a
concern
for
at
least
two
reasons:
the
first
is
the
cognitive
load
on
the
developer
of
remembering
all
of
the
<a href="#dfn-term" title="term" class="tref internalDFN">
terms
</a>,
and
the
second
is
the
serialized
size
of
the
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
if
it
is
specified
inline.
In
order
to
address
these
issues,
the
concept
of
a
<a href="#dfn-compact-iri" title="compact-iri" class="tref internalDFN">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
is
introduced.
</p>
<p>
A
<dfn id="dfn-compact-iri" title="compact-iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</dfn>
is
a
way
of
expressing
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
using
a
<em>
prefix
</em>
and
<em>
suffix
</em>
separated
by
a
colon
(
<code>:
</code>
)
which
is
similar
to
the
<cite>
<a href="http://www.w3.org/TR/rdfa-core/#s_curies">
CURIE
Syntax
</a>
</cite>
in
[
<cite>
<a href="#bib-RDFA-CORE" class="bibref">
RDFA-CORE
</a>
</cite>
].
The
<dfn id="dfn-prefix" title="prefix">
prefix
</dfn>
is
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
taken
from
the
<a href="#dfn-active-context" title="active-context" class="tref internalDFN">
active
context
</a>
and
is
a
short
string
identifying
a
particular
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
in
a
JSON-LD
document.
For
example,
the
prefix
<code>
foaf
</code>
may
be
used
as
a
short
hand
for
the
Friend-of-a-Friend
vocabulary,
which
is
identified
using
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
<code>
http://xmlns.com/foaf/0.1/
</code>.
A
developer
may
append
any
of
the
FOAF
vocabulary
terms
to
the
end
of
the
prefix
to
specify
a
short-hand
version
of
the
<a href="#dfn-absolute-iri" title="absolute-iri" class="tref internalDFN">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
for
the
vocabulary
term.
For
example,
<code>
foaf:name
</code>
would
be
expanded
out
to
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
<code>
http://xmlns.com/foaf/0.1/name
</code>.
Instead
of
having
to
remember
and
type
out
the
entire
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>,
the
developer
can
instead
use
the
prefix
in
their
JSON-LD
markup.
</p>
<p>
<a href="#dfn-prefix" title="prefix" class="tref internalDFN">
Prefixes
</a>
are
expanded
when
the
form
of
the
value
is
a
<a href="#dfn-compact-iri" title="compact-iri" class="tref internalDFN">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
represented
as
a
<code>
prefix:suffix
</code>
combination,
and
the
prefix
matches
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
defined
within
the
<a href="#dfn-active-context" title="active-context" class="tref internalDFN">
active
context
</a>:
</p>
<del class="diff-old">  {
  "":
  {
    ""
...
  },
  "": "Dave Longley",
...
</del>
  <div class="example"><div class="example-title"><span>Example 15</span>: Prefix expansion</div><pre class="example">{
<ins class="diff-chg">  "<span class="diff">@context</span>":
  {
    "<span class="diff">foaf</span>": "<span class="diff">http://xmlns.com/foaf/0.1/</span>"
...
  },
  "<span class="diff">foaf:name</span>": "Dave Longley",
...
</ins>
}
</pre>
</div>
<p>
<code>
foaf:name
</code>
above
will
automatically
expand
out
to
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
<code>
http://xmlns.com/foaf/0.1/name
</code>.
</p>
<p>
Terms
are
interpreted
as
<a href="#dfn-compact-iri" title="compact-iri" class="tref internalDFN">
compact
IRIs
</a>
if
they
contain
at
least
one
colon
and
the
first
colon
is
not
followed
by
two
slashes
(
<code>
//
</code>,
as
in
<code>
http://example.com
</code>
).
To
generate
the
full
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
the
value
is
first
split
into
a
<em>
prefix
</em>
and
<em>
suffix
</em>
at
the
first
occurrence
of
a
colon
(
<code>:
</code>
).
If
the
<a href="#dfn-active-context" title="active-context" class="tref internalDFN">
active
context
</a>
contains
a
term
mapping
for
<em>
prefix
</em>,
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
is
generated
by
prepending
the
mapped
<em>
prefix
</em>
to
the
(possibly
empty)
<em>
suffix
</em>
using
textual
concatenation.
If
no
prefix
mapping
is
defined,
the
value
is
interpreted
as
an
<a href="#dfn-absolute-iri" title="absolute-iri" class="tref internalDFN">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
If
the
prefix
is
an
underscore
(
<code>
_
</code>
),
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
remains
unchanged.
</p>
<p>
Consider
the
following
example:
</p>
<del class="diff-old">  {
  "@context":
  {


  },
  "@id": "http://example.org/library",
  "@type": ,
  :
  {
    "@id": "http://example.org/library/the-republic",
    "@type": ,
    : "Plato",
    : "The Republic",
    :
    {
      "@id": "http://example.org/library/the-republic#introduction",
      "@type": ,
      : "An introductory chapter on The Republic.",
      : "The Introduction"
    }
  }
</del>
  <div class="example"><div class="example-title"><span>Example 16</span>: Compact IRIs</div><pre class="example">{
<ins class="diff-chg">  "@context":
  {
</ins>    <span class="diff">"dc": "http://purl.org/dc/elements/1.1/",</span>
    <span class="diff">"ex": "http://example.org/vocab#"</span>
<ins class="diff-chg">
  },
  "@id": "http://example.org/library",
  "@type": <span class="diff">"ex:Library"</span>,
</ins>  <span class="diff">"ex:contains"</span>:
<ins class="diff-chg">
  {
    "@id": "http://example.org/library/the-republic",
    "@type": <span class="diff">"ex:Book"</span>,
</ins>    <span class="diff">"dc:creator"</span>: "Plato",
    <span class="diff">"dc:title"</span>: "The Republic",
    <span class="diff">"ex:contains"</span>:
<ins class="diff-chg">
    {
      "@id": "http://example.org/library/the-republic#introduction",
      "@type": <span class="diff">"ex:Chapter"</span>,
</ins>      <span class="diff">"dc:description"</span>: "An introductory chapter on The Republic.",
      <span class="diff">"dc:title"</span>: "The Introduction"
<ins class="diff-chg">
    }
  }
</ins>
}
</pre>
</div>
<p>
In
this
example,
two
different
vocabularies
are
referred
to
using
prefixes.
Those
prefixes
are
then
used
as
type
and
property
values
using
the
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
<code>
prefix:suffix
</code>
notation.
</p>
<p>
It's
also
possible
to
use
compact
IRIs
within
the
context
as
shown
in
the
following
example:
</p>
<del class="diff-old">  {
  "@context":
  {
    "xsd": "http://www.w3.org/2001/XMLSchema#",
    ,
    : { "@type": "@id" },
    "picture": { "@id": , "@type": "@id" }
  },
  "@id": "http://me.markus-lanthaler.com/",
  "@type": "foaf:Person",
  "foaf:name": "Markus Lanthaler",
  "foaf:homepage": "http://www.markus-lanthaler.com/",
  "picture": "http://twitter.com/account/profile_image/markuslanthaler"
</del>
  <div class="example"><div class="example-title"><span>Example 17</span>: Using vocabularies</div><pre class="example">{
<ins class="diff-chg">  "@context":
  {
    "xsd": "http://www.w3.org/2001/XMLSchema#",
</ins>    <span class="diff">"foaf": "http://xmlns.com/foaf/0.1/"</span>,
    <span class="diff">"foaf:homepage"</span>: { "@type": "@id" },
<ins class="diff-chg">
    "picture": { "@id": <span class="diff">"foaf:depiction"</span>, "@type": "@id" }
  },
  "@id": "http://me.markus-lanthaler.com/",
  "@type": "foaf:Person",
  "foaf:name": "Markus Lanthaler",
  "foaf:homepage": "http://www.markus-lanthaler.com/",
  "picture": "http://twitter.com/account/profile_image/markuslanthaler"
</ins>
}
</pre>
</div>
</section>
<section id="typed-values">
<h3>
<span class="secno">
6.2
</span>
Typed
Values
</h3>
<p>
A
value
with
an
associated
type,
also
known
as
a
<a href="#dfn-typed-value" title="typed-value" class="tref internalDFN">
typed
value
</a>,
is
indicated
by
associating
a
value
with
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
which
indicates
the
value's
type.
Typed
values
may
be
expressed
in
JSON-LD
in
three
ways:
</p>
<ol>
<li>
By
utilizing
the
<code>
@type
</code>
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keyword
</a>
when
defining
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
within
a
<code>
@context
</code>
section.
</li>
<li>
By
utilizing
an
<a href="#dfn-expanded-typed-value" title="expanded-typed-value" class="tref internalDFN">
expanded
typed
value
</a>.
</li>
<li>
By
using
a
native
JSON
type
such
as
<a href="#dfn-number" title="number" class="tref internalDFN">
number
</a>,
<a href="#dfn-true" title="true" class="tref internalDFN">
true
</a>,
or
<a href="#dfn-false" title="false" class="tref internalDFN">
false
</a>.
</li>
</ol>
<p>
The
first
example
uses
the
<code>
@type
</code>
keyword
to
associate
a
type
with
a
particular
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
in
the
<code>
@context
</code>:
</p>
<del class="diff-old">{
  "@context":
  {
    "modified":
    {
      "@id": "http://purl.org/dc/terms/modified",
      "@type": "http://www.w3.org/2001/XMLSchema#dateTime"
    }
  },
...
  "@id": "http://example.com/docs/1",
  "modified": "2010-05-29T14:17:39+02:00",
...
</del>
<div class="example"><div class="example-title"><span>Example 18</span>: Expanded term definition with type coercion</div><pre class="example">{
  <span class="diff">"@context":
<ins class="diff-chg">  {
    "modified":
    {
      "@id": "http://purl.org/dc/terms/modified",
      "@type": "http://www.w3.org/2001/XMLSchema#dateTime"
    }
  },</span>
...
  "@id": "http://example.com/docs/1",
  "modified": "2010-05-29T14:17:39+02:00",
...
</ins>
}
</pre>
</div>
<p>
The
<em>
modified
</em>
key's
value
above
is
automatically
type
coerced
to
a
dateTime
value
because
of
the
information
specified
in
the
<code>
@context
</code>.
A
JSON-LD
processor
will
interpret
the
markup
above
like
so:
</p>
<table class="example">
<thead>
<tr>
<th>
Subject
</th>
<th>
Property
</th>
<th>
Value
</th>
<th>
Value
Type
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
http://example.com/docs/1
</td>
<td>
http://purl.org/dc/terms/modified
</td>
<td>
2010-05-29T14:17:39+02:00
</td>
<td>
http://www.w3.org/2001/XMLSchema#dateTime
</td>
</tr>
</tbody>
</table>
<p>
The
second
example
uses
the
expanded
form
of
setting
the
type
information
in
the
body
of
a
JSON-LD
document:
</p>
<del class="diff-old">{
  "@context":
  {
    "modified":
    {
      "@id": "http://purl.org/dc/terms/modified"
    }
  },
...
  "modified":
  {
    "@value": "2010-05-29T14:17:39+02:00",
    "@type": "http://www.w3.org/2001/XMLSchema#dateTime"
  }
...
</del>
<div class="example"><div class="example-title"><span>Example 19</span>: Expanded value with type</div><pre class="example">{
<ins class="diff-chg">  "@context":
  {
    "modified":
    {
      "@id": "http://purl.org/dc/terms/modified"
    }
  },
...
  "modified":
</ins>  <span class="diff">{
<ins class="diff-chg">
    "@value": "2010-05-29T14:17:39+02:00",
    "@type": "http://www.w3.org/2001/XMLSchema#dateTime"
  }</span>
...
</ins>
}
</pre>
</div>
<p>
Both
examples
above
would
generate
the
value
<code>
2010-05-29T14:17:39+02:00
</code>
with
the
type
<code>
http://www.w3.org/2001/XMLSchema#dateTime
</code>.
Note
that
it
is
also
possible
to
use
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
or
a
<a href="#dfn-compact-iri" title="compact-iri" class="tref internalDFN">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
to
express
the
value
of
a
type.
</p>
<p>
The
<code>
@type
</code>
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keyword
</a>
is
also
used
to
associate
a
type
with
a
<a href="#dfn-node" title="node" class="tref internalDFN">
node
</a>.
The
concept
of
a
<a href="#dfn-node-type" title="node-type" class="tref internalDFN">
node
type
</a>
and
a
<a href="#dfn-value-type" title="value-type" class="tref internalDFN">
value
type
</a>
are
different.
</p>
<p>
Generally
speaking,
a
<dfn id="dfn-node-type" title="node-type">
node
type
</dfn>
specifies
the
type
of
thing
that
is
being
described,
like
a
person,
place,
event,
or
web
page.
A
<dfn id="dfn-value-type" title="value-type">
value
type
</dfn>
specifies
the
unit
of
measurement
for
a
particular
value,
such
as
a
date,
meter,
or
light
year.
</p>
<del class="diff-old">{
...
  "@id": "http://example.org/posts#TripToWestVirginia",
  ,   &lt;--- This is a node type
  "modified":
  {
    "@value": "2010-05-29T14:17:39+02:00",
     &lt;--- This is a value type
  }
...
</del>
<div class="example"><div class="example-title"><span>Example 20</span>: Example demonstrating the context-sensitivity for @type</div><pre class="example">{
<ins class="diff-chg">...
  "@id": "http://example.org/posts#TripToWestVirginia",
</ins>  <span class="diff">"@type": "http://schema.org/BlogPosting"</span>,   &lt;--- This is a node type
<ins class="diff-chg">
  "modified":
  {
    "@value": "2010-05-29T14:17:39+02:00",
</ins>    <span class="diff">"@type": "http://www.w3.org/2001/XMLSchema#dateTime"</span> &lt;--- This is a value type
<ins class="diff-chg">
  }
...
</ins>
}
</pre>
</div>
<p>
The
first
use
of
<code>
@type
</code>
associates
a
<a href="#dfn-node-type" title="node-type" class="tref internalDFN">
node
type
</a>
(
<code>
http://schema.org/BlogPosting
</code>
)
with
the
<a href="#dfn-node" title="node" class="tref internalDFN">
node
</a>,
which
is
expressed
using
the
<code>
@id
</code>
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keyword
</a>.
The
second
use
of
<code>
@type
</code>
associates
a
<a href="#dfn-value-type" title="value-type" class="tref internalDFN">
value
type
</a>
(
<code>
http://www.w3.org/2001/XMLSchema#dateTime
</code>
)
with
the
value
expressed
using
the
<code>
@value
</code>
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keyword
</a>.
As
a
general
rule,
when
<code>
@value
</code>
and
<code>
@type
</code>
are
used
in
the
same
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
object
</a>,
the
<code>
@type
</code>
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keyword
</a>
is
expressing
a
<a href="#dfn-value-type" title="value-type" class="tref internalDFN">
value
type
</a>.
Otherwise,
the
<code>
@type
</code>
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keyword
</a>
is
expressing
a
<a href="#dfn-node-type" title="node-type" class="tref internalDFN">
node
type
</a>.
The
markup
above
expresses
the
following
data:
</p>
<table class="example">
<thead>
<tr>
<th>
Subject
</th>
<th>
Property
</th>
<th>
Value
</th>
<th>
Value
Type
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
http://example.org/posts#TripToWestVirginia
</td>
<td>
http://www.w3.org/1999/02/22-rdf-syntax-ns#type
</td>
<td>
http://schema.org/BlogPosting
</td>
<td style="text-align:center;">
-
</td>
</tr>
<tr>
<td>
http://example.org/posts#TripToWestVirginia
</td>
<td>
http://purl.org/dc/terms/modified
</td>
<td>
2010-05-29T14:17:39+02:00
</td>
<td>
http://www.w3.org/2001/XMLSchema#dateTime
</td>
</tr>
</tbody>
</table>
</section>
<section id="type-coercion">
<h3>
<span class="secno">
6.3
</span>
Type
Coercion
</h3>
<p>
JSON-LD
supports
the
coercion
of
values
to
particular
data
types.
Type
<dfn id="dfn-coercion" title="coercion">
coercion
</dfn>
allows
someone
deploying
JSON-LD
to
coerce
the
incoming
or
outgoing
values
to
the
proper
data
type
based
on
a
mapping
of
data
type
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>
to
<a href="#dfn-term" title="term" class="tref internalDFN">
terms
</a>.
Using
type
coercion,
value
representation
is
preserved
without
requiring
the
data
type
to
be
specified
with
each
piece
of
data.
</p>
<p>
Type
coercion
is
specified
within
an
<a href="#dfn-expanded-term-definition" title="expanded-term-definition" class="tref internalDFN">
expanded
term
definition
</a>
using
the
<code>
@type
</code>
key.
The
value
of
this
key
expands
to
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
Alternatively,
the
<del class="diff-old">keyword
</del>
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
<ins class="diff-chg">keywords
</ins>
</a>
<code>
@id
</code>
<ins class="diff-new">or
</ins><code><ins class="diff-new">
@vocab
</ins></code>
may
be
used
as
value
to
indicate
that
within
the
body
of
a
JSON-LD
document,
a
<a href="#dfn-string" title="string" class="tref internalDFN">
string
</a>
value
of
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
coerced
to
<code>
@id
</code>
<ins class="diff-new">or
</ins><code><ins class="diff-new">
@vocab
</ins></code>
is
to
be
interpreted
as
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
<ins class="diff-new">The
difference
between
</ins><code><ins class="diff-new">
@id
</ins></code><ins class="diff-new">
and
</ins><code><ins class="diff-new">
@vocab
</ins></code><ins class="diff-new">
is
how
values
are
expanded
to
</ins><a href="#dfn-absolute-iri" title="absolute-iri" class="tref internalDFN"><ins class="diff-new">
absolute
IRIs
</ins></a>.<code><ins class="diff-new">
@vocab
</ins></code><ins class="diff-new">
first
tries
to
expand
the
value
by
interpreting
it
as
</ins><a href="#dfn-term" title="term" class="tref internalDFN"><ins class="diff-new">
term
</ins></a>.<ins class="diff-new">
If
no
matching
</ins><a href="#dfn-term" title="term" class="tref internalDFN"><ins class="diff-new">
term
</ins></a><ins class="diff-new">
is
found
in
the
</ins><a href="#dfn-active-context" title="active-context" class="tref internalDFN"><ins class="diff-new">
active
context
</ins></a>,<ins class="diff-new">
it
tries
to
expand
it
as
</ins><a href="#dfn-compact-iri" title="compact-iri" class="tref internalDFN"><ins class="diff-new">
compact
</ins><abbr title="Internationalized Resource Identifier"><ins class="diff-new">
IRI
</ins></abbr></a><ins class="diff-new">
or
</ins><a href="#dfn-absolute-iri" title="absolute-iri" class="tref internalDFN"><ins class="diff-new">
absolute
</ins><abbr title="Internationalized Resource Identifier"><ins class="diff-new">
IRI
</ins></abbr></a><ins class="diff-new">
if
there's
a
colon
in
the
value;
otherwise,
it
will
expand
the
value
using
the
</ins><a href="#dfn-active-context" title="active-context" class="tref internalDFN"><ins class="diff-new">
active
context's
</ins></a><ins class="diff-new">
vocabulary
mapping,
if
present,
or
by
interpreting
it
as
</ins><a href="#dfn-relative-iri" title="relative-iri" class="tref internalDFN"><ins class="diff-new">
relative
</ins><abbr title="Internationalized Resource Identifier"><ins class="diff-new">
IRI
</ins></abbr></a>.<ins class="diff-new">
Values
coerced
to
</ins><code><ins class="diff-new">
@id
</ins></code><ins class="diff-new">
in
contrast
are
expanded
as
</ins><a href="#dfn-compact-iri" title="compact-iri" class="tref internalDFN"><ins class="diff-new">
compact
</ins><abbr title="Internationalized Resource Identifier"><ins class="diff-new">
IRI
</ins></abbr></a><ins class="diff-new">
or
</ins><a href="#dfn-absolute-iri" title="absolute-iri" class="tref internalDFN"><ins class="diff-new">
absolute
</ins><abbr title="Internationalized Resource Identifier"><ins class="diff-new">
IRI
</ins></abbr></a><ins class="diff-new">
if
a
colon
is
present;
otherwise,
they
are
interpreted
as
</ins><a href="#dfn-relative-iri" title="relative-iri" class="tref internalDFN"><ins class="diff-new">
relative
</ins><abbr title="Internationalized Resource Identifier"><ins class="diff-new">
IRI
</ins></abbr></a>.
</p>
<p>
<a href="#dfn-term" title="term" class="tref internalDFN">
Terms
</a>
or
<a href="#dfn-compact-iri" title="compact-iri" class="tref internalDFN">
compact
IRIs
</a>
used
as
the
value
of
a
<code>
@type
</code>
key
may
be
defined
within
the
same
context.
This
means
that
one
may
specify
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
like
<code>
xsd
</code>
and
then
use
<code>
xsd:integer
</code>
within
the
same
context
definition.
</p>
<p>
The
example
below
demonstrates
how
a
JSON-LD
author
can
coerce
values
to
<a href="#dfn-typed-value" title="typed-value" class="tref internalDFN">
typed
values
</a>,
IRIs,
and
lists.
</p>
<del class="diff-old">{
  "@context":
  {
    "xsd": "http://www.w3.org/2001/XMLSchema#",
    "name": "http://xmlns.com/foaf/0.1/name",
    "age":
    {
      "@id": "http://xmlns.com/foaf/0.1/age",
      "@type": "xsd:integer"
    },
    "homepage":
    {
      "@id": "http://xmlns.com/foaf/0.1/homepage",
      "@type": "@id",
      "@container": "@list"
    }
  },
  "@id": "http://example.com/people#john",
  "name": "John Smith",
  "age": ,
  "homepage":
  [
    "http://personal.example.org/",
    "http://work.example.com/jsmith/"
  ]
</del>
<div class="example"><div class="example-title"><span>Example 21</span>: Expanded term definition with types</div><pre class="example">{
<ins class="diff-chg">  "@context":
  {
    "xsd": "http://www.w3.org/2001/XMLSchema#",
    "name": "http://xmlns.com/foaf/0.1/name",
    "age":
</ins>    <span class="diff">{
<ins class="diff-chg">
      "@id": "http://xmlns.com/foaf/0.1/age",
      "@type": "xsd:integer"
    }</span>,
    "homepage":
</ins>    <span class="diff">{
<ins class="diff-chg">
      "@id": "http://xmlns.com/foaf/0.1/homepage",
      "@type": "@id",
      "@container": "@list"
    }</span>
  },
  "@id": "http://example.com/people#john",
  "name": "John Smith",
  "age": <span class="diff">"41"</span>,
  "homepage":
</ins>  <span class="diff">[
<ins class="diff-chg">
    "http://personal.example.org/",
    "http://work.example.com/jsmith/"
  ]</span>
</ins>
}
</pre>
</div>
<p>
The
markup
shown
above
would
generate
the
following
data.
The
data
has
no
inherent
order
except
for
the
values
of
the
<code>
http://schema.org/homepage
</code>
property
which
represent
an
ordered
list.
</p>
<table class="example">
<thead>
<tr>
<th>
Subject
</th>
<th>
Property
</th>
<th>
Value
</th>
<th>
Value
Type
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
http://example.com/people#john
</td>
<td>
http://xmlns.com/foaf/0.1/name
</td>
<td>
John
Smith
</td>
<td>
&nbsp;
</td>
</tr>
<tr>
<td>
http://example.com/people#john
</td>
<td>
http://xmlns.com/foaf/0.1/age
</td>
<td>
41
</td>
<td>
http://www.w3.org/2001/XMLSchema#integer
</td>
</tr>
<tr>
<td rowspan="2">
http://example.com/people#john
</td>
<td rowspan="2">
http://xmlns.com/foaf/0.1/homepage
</td>
<td>
http://personal.example.org/
</td>
<td>
&nbsp;
</td>
</tr>
<tr>
<td>
http://work.example.com/jsmith/
</td>
<td>
&nbsp;
</td>
</tr>
</tbody>
</table>
<p>
Terms
may
also
be
defined
using
<a href="#dfn-absolute-iri" title="absolute-iri" class="tref internalDFN">
absolute
IRIs
</a>
or
<a href="#dfn-compact-iri" title="compact-iri" class="tref internalDFN">
compact
IRIs
</a>.
This
allows
coercion
rules
to
be
applied
to
keys
which
are
not
represented
as
a
simple
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>.
For
example:
</p>
<del class="diff-old">{
  "@context":
  {
    "foaf": "http://xmlns.com/foaf/0.1/",
    "":
    {
      ,
      "@type": "xsd:integer"
    },
    "":
    {
      "@type": "@id"
    }
  },
  "foaf:name": "John Smith",
  "": "41",
  "":
  [
    "http://personal.example.org/",
    "http://work.example.com/jsmith/"
  ]
</del>
<div class="example"><div class="example-title"><span>Example 22</span>: Term definitions using compact and absolute IRIs</div><pre class="example">{
<ins class="diff-chg">  "@context":
  {
    "foaf": "http://xmlns.com/foaf/0.1/",
    "<span class="diff">foaf:age</span>":
    {
</ins>      <span class="diff">"@id": "http://xmlns.com/foaf/0.1/age"</span>,
<ins class="diff-chg">
      "@type": "xsd:integer"
    },
    "<span class="diff">http://xmlns.com/foaf/0.1/homepage</span>":
    {
      "@type": "@id"
    }
  },
  "foaf:name": "John Smith",
  "<span class="diff">foaf:age</span>": "41",
  "<span class="diff">http://xmlns.com/foaf/0.1/homepage</span>":
  [
    "http://personal.example.org/",
    "http://work.example.com/jsmith/"
  ]
</ins>
}
</pre>
</div>
<p>
In
this
case
the
<code>
@id
</code>
definition
in
the
term
definition
is
optional,
but
if
it
does
exist,
the
<a href="#dfn-compact-iri" title="compact-iri" class="tref internalDFN">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
or
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
is
treated
as
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
(not
a
<code>
prefix:suffix
</code>
construct)
so
that
the
actual
definition
of
a
<a href="#dfn-prefix" title="prefix" class="tref internalDFN">
prefix
</a>
becomes
unnecessary.
Type
coercion
is
performed
using
the
unexpanded
value
of
the
key
if
there
is
an
exact
match
for
the
key
in
the
<a href="#dfn-active-context" title="active-context" class="tref internalDFN">
active
context
</a>.
</p>
<div class="note">
<div class="note-title">
<span>
Note
</span>
</div>
<p class="">
Keys
in
the
context
are
treated
as
<a href="#dfn-term" title="term" class="tref internalDFN">
terms
</a>
for
the
purpose
of
expansion
and
value
coercion.
At
times,
this
may
result
in
multiple
representations
for
the
same
expanded
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>.
For
example,
one
could
specify
that
<code>
dog
</code>
and
<code>
cat
</code>
both
expanded
to
<code>
http://example.com/vocab#animal
</code>.
Doing
this
could
be
useful
for
establishing
different
type
coercion
or
language
specification
rules.
It
also
allows
a
<a href="#dfn-compact-iri" title="compact-iri" class="tref internalDFN">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
(or
even
an
absolute
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
)
to
be
defined
as
something
else
entirely.
For
example,
one
could
specify
that
the
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
<code>
http://example.org/zoo
</code>
should
expand
to
<code>
http://example.org/river
</code>,
but
this
usage
is
discouraged
because
it
would
lead
to
a
great
deal
of
confusion
among
developers
attempting
to
understand
the
JSON-LD
document.
</p>
</div>
</section>
<section id="advanced-context-usage">
<h3>
<span class="secno">
6.4
</span>
Advanced
Context
Usage
</h3>
<p>
Section
<a class="sec-ref" href="#the-context">
<span class="secno">
5.1
</span>
<span class="sec-title">
The
Context
</span>
</a>
introduced
the
basics
of
what
makes
JSON-LD
work.
This
section
expands
on
the
basic
principles
of
the
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
and
demonstrates
how
more
advanced
use
cases
can
be
achieved
using
JSON-LD.
</p>
<p>
In
general,
contexts
may
be
used
at
any
time
a
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
object
</a>
is
defined.
The
only
time
that
one
cannot
express
a
context
is
inside
a
context
definition
itself.
For
example,
a
<a href="#dfn-json-ld-document" title="json-ld-document" class="tref internalDFN">
JSON-LD
document
</a>
may
use
more
than
one
context
at
different
points
in
a
document:
</p>
<del class="diff-old">    [
  {

    "name": "Manu Sporny",
    "homepage": "http://manu.sporny.org/",
    "depiction": "http://twitter.com/account/profile_image/manusporny"
  },
  {

    "name": "The Empire State Building",
    "description": "The Empire State Building is a 102-story landmark in New York City.",
    "geo": {
      "latitude": "40.75",
      "longitude": "73.98"
    }
  }
</del>
  <div class="example"><div class="example-title"><span>Example 23</span>: Using multiple contexts</div><pre class="example">[
<ins class="diff-chg">  {
</ins>    <span class="diff">"@context": "http://example.org/contexts/person.jsonld",</span>
<ins class="diff-chg">
    "name": "Manu Sporny",
    "homepage": "http://manu.sporny.org/",
    "depiction": "http://twitter.com/account/profile_image/manusporny"
  },
  {
</ins>    <span class="diff">"@context": "http://example.org/contexts/place.jsonld",</span>
<ins class="diff-chg">
    "name": "The Empire State Building",
    "description": "The Empire State Building is a 102-story landmark in New York City.",
    "geo": {
      "latitude": "40.75",
      "longitude": "73.98"
    }
  }
</ins>
]
</pre>
</div>
<p>
Duplicate
context
<a href="#dfn-term" title="term" class="tref internalDFN">
terms
</a>
are
overridden
using
a
last-defined-wins
mechanism.
</p>
<del class="diff-old">    {
  "@context":
  {
    "name": "http://example.com/person#name",
    "details": "http://example.com/person#details"
  },
  "": "Markus Lanthaler",
  ...
  "details":
  {
    "@context": {
      "name": "http://example.com/organization#name"
    },
    "": "Graz University of Technology"
  }
</del>
  <div class="example"><div class="example-title"><span>Example 24</span>: Scoped contexts within node objects</div><pre class="example">{
  <span class="diff">"@context":
<ins class="diff-chg">  {
    "name": "http://example.com/person#name",
    "details": "http://example.com/person#details"
  },</span>
  "<span class="diff">name</span>": "Markus Lanthaler",
  ...
  "details":
  {
</ins>    <span class="diff">"@context": {
<ins class="diff-chg">
      "name": "http://example.com/organization#name"
    },</span>
    "<span class="diff">name</span>": "Graz University of Technology"
  }
</ins>
}
</pre>
</div>
<p>
In
the
example
above,
the
<code>
name
</code>
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
is
overridden
in
the
more
deeply
nested
<code>
details
</code>
structure.
Note
that
this
is
rarely
a
good
authoring
practice
and
is
typically
used
when
working
with
legacy
applications
that
depend
on
a
specific
structure
of
the
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
object
</a>.
If
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
is
redefined
within
a
context,
all
previous
rules
associated
with
the
previous
definition
are
removed.
If
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
is
redefined
to
<code>
null
</code>,
the
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
is
effectively
removed
from
the
list
of
<a href="#dfn-term" title="term" class="tref internalDFN">
terms
</a>
defined
in
the
<a href="#dfn-active-context" title="active-context" class="tref internalDFN">
active
context
</a>.
</p>
<p>
Multiple
contexts
may
be
combined
using
an
<a href="#dfn-array" title="array" class="tref internalDFN">
array
</a>,
which
is
processed
in
order.
The
set
of
contexts
defined
within
a
specific
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
object
</a>
are
referred
to
as
<dfn id="dfn-local-context" title="local-context">
local
contexts
</dfn>.
The
<dfn id="dfn-active-context" title="active-context">
active
context
</dfn>
refers
to
the
accumulation
of
<a href="#dfn-local-context" title="local-context" class="tref internalDFN">
local
contexts
</a>
that
are
in
scope
at
a
specific
point
within
the
document.
Setting
a
<a href="#dfn-local-context" title="local-context" class="tref internalDFN">
local
context
</a>
to
<code>
null
</code>
effectively
resets
the
<a href="#dfn-active-context" title="active-context" class="tref internalDFN">
active
context
</a>
to
an
empty
context.
The
following
example
specifies
an
external
context
and
then
layers
an
embedded
context
on
top
of
the
external
context:
</p>
<del class="diff-old">    {
  "@context": [
    "http://json-ld.org/contexts/person.jsonld",
    {
      "pic": "http://xmlns.com/foaf/0.1/depiction"
    }
  ],
  "name": "Manu Sporny",
  "homepage": "http://manu.sporny.org/",

</del>
  <div class="example"><div class="example-title"><span>Example 25</span>: Combining external and local contexts</div><pre class="example">{
  <span class="diff">"@context": [
<ins class="diff-chg">    "http://json-ld.org/contexts/person.jsonld",
    {
      "pic": "http://xmlns.com/foaf/0.1/depiction"
    }
  ],</span>
  "name": "Manu Sporny",
  "homepage": "http://manu.sporny.org/",
</ins>  <span class="diff">"pic": "http://twitter.com/account/profile_image/manusporny"</span>
}
</pre>
</div>
<div class="note">
<div class="note-title">
<span>
Note
</span>
</div>
<p class="">
It
is
a
best
practice
to
put
the
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
definition
at
the
top
of
the
JSON-LD
document.
</p>
</div>
<div class="note">
<div class="note-title">
<span>
Note
</span>
</div>
<p class="">
<del class="diff-old">While
it
is
possible
to
define
a
compact
IRI
,
or
an
absolute
IRI
to
expand
to
some
other
unrelated
IRI
(for
example,
foaf:name
expanding
to
http://example.org/unrelated#species
),
such
usage
is
strongly
discouraged.
Note
</del>
To
avoid
forward-compatibility
issues,
<a href="#dfn-term" title="term" class="tref internalDFN">
terms
</a>
starting
with
an&nbsp;
<code>
@
</code>
character
are
to
be
avoided
as
they
might
be
used
as
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keywords
</a>
in
future
versions
of
JSON-LD.
Furthermore,
the
use
of
empty
<a href="#dfn-term" title="term" class="tref internalDFN">
terms
</a>
(
<code>
""
</code>
)
is
discouraged
as
not
all
programming
languages
are
able
to
handle
empty
property
names.
</p>
</div>
</section>
<section id="interpreting-json-as-json-ld">
<h3>
<span class="secno">
<del class="diff-old">6.4.1
</del>
<ins class="diff-chg">6.5
</ins>
</span>
Interpreting
JSON
as
JSON-LD
</h3>
<p>
Ordinary
JSON
documents
can
be
interpreted
as
JSON-LD
by
referencing
a
JSON-LD
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
document
in
an
HTTP
Link
Header.
Doing
so
allows
JSON
to
be
unambiguously
machine-readable
without
requiring
developers
to
drastically
change
their
markup
and
provides
an
upgrade
path
for
existing
infrastructure
without
breaking
existing
clients
that
rely
on
the
<code>
application/json
</code>
media
type.
</p>
<p>
In
order
to
use
an
external
context
with
an
ordinary
JSON
document,
an
author
<em title="must" class="rfc2119">
must
</em>
specify
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
to
a
valid
<a href="#dfn-json-ld-document" title="json-ld-document" class="tref internalDFN">
JSON-LD
document
</a>
in
an
HTTP
Link
Header
[
<cite>
<a href="#bib-RFC5988" class="bibref">
RFC5988
</a>
</cite>
]
using
the
<code>
http://www.w3.org/ns/json-ld#context
</code>
link
relation.
The
referenced
document
<em title="must" class="rfc2119">
must
</em>
have
a
top-level
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
object
</a>.
The
<code>
@context
</code>
subtree
within
that
object
is
added
to
the
top-level
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
object
</a>
of
the
referencing
document.
If
an
<a href="#dfn-array" title="array" class="tref internalDFN">
array
</a>
is
at
the
top-level
of
the
referencing
document
and
its
items
are
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
objects
</a>,
the
<code>
@context
</code>
subtree
is
added
to
all
<a href="#dfn-array" title="array" class="tref internalDFN">
array
</a>
items.
All
extra
information
located
outside
of
the
<code>
@context
</code>
subtree
in
the
referenced
document
<em title="must" class="rfc2119">
must
</em>
be
discarded.
Effectively
this
means
that
the
<a href="#dfn-active-context" title="active-context" class="tref internalDFN">
active
context
</a>
is
initialized
with
the
referenced
external
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>.
</p>
<p>
The
following
example
demonstrates
the
use
of
an
external
context
with
an
ordinary
JSON
document:
</p>
<del class="diff-old">      GET /ordinary-json-document.json HTTP/1.1
Host: example.com
Accept: application/ld+json,application/json,*/*;q=0.1
====================================
HTTP/1.0 200 OK
...
Content-Type:
{
  "name": "Markus Lanthaler",
  "homepage": "http://www.markus-lanthaler.com/",
  "image": "http://twitter.com/account/profile_image/markuslanthaler"
</del>
  <div class="example"><div class="example-title"><span>Example 26</span>: Referencing a JSON-LD context from a JSON document via an HTTP Link Header</div><pre class="example">GET /ordinary-json-document.json HTTP/1.1
<ins class="diff-chg">Host: example.com
Accept: application/ld+json,application/json,*/*;q=0.1

====================================

HTTP/1.0 200 OK
...
Content-Type: <span class="diff">application/json</span>
</ins><span class="diff">Link: &lt;http://json-ld.org/contexts/person.jsonld&gt;; rel="http://www.w3.org/ns/json-ld#context"; type="application/ld+json"</span>
<ins class="diff-chg">

{
  "name": "Markus Lanthaler",
  "homepage": "http://www.markus-lanthaler.com/",
  "image": "http://twitter.com/account/profile_image/markuslanthaler"
</ins>
}
</pre>
</div>
<p>
Please
note
that
<a href="#dfn-json-ld-document" title="json-ld-document" class="tref internalDFN">
JSON-LD
documents
</a>
served
with
the
<code>
application/ld+json
</code>
media
type
<em title="must" class="rfc2119">
must
</em>
have
all
context
information,
including
references
to
external
contexts,
within
the
body
of
the
document.
Contexts
linked
via
a
<code>
http://www.w3.org/ns/json-ld#context
</code>
HTTP
Link
Header
<em title="must" class="rfc2119">
must
</em>
be
ignored
for
such
documents.
</p>
</section>
<section id="string-internationalization">
<h3>
<span class="secno">
<del class="diff-old">6.5
</del>
<ins class="diff-chg">6.6
</ins>
</span>
String
Internationalization
</h3>
<p>
At
times,
it
is
important
to
annotate
a
<a href="#dfn-string" title="string" class="tref internalDFN">
string
</a>
with
its
language.
In
JSON-LD
this
is
possible
in
a
variety
of
ways.
First,
it
is
possible
to
define
a
default
language
for
a
JSON-LD
document
by
setting
the
<code>
@language
</code>
key
in
the
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>:
</p>
<del class="diff-old">  {
  "@context":
  {
    ...
    "@language": "ja"
  },
  "name": ,
  "occupation":
</del>
  <div class="example"><div class="example-title"><span>Example 27</span>: Setting the default language of a JSON-LD document</div><pre class="example">{
  <span class="diff">"@context":
<ins class="diff-chg">  {
    ...
    "@language": "ja"
  }</span>,
  "name": <span class="diff">"花澄"</span>,
  "occupation": <span class="diff">"科学者"</span>
</ins>
}
</pre>
</div>
<p>
The
example
above
would
associate
the
<code>
ja
</code>
language
code
with
the
two
<a href="#dfn-string" title="string" class="tref internalDFN">
strings
</a>
<em>
花澄
</em>
and
<em>
科学者
</em>.
Languages
codes
are
defined
in
[
<cite>
<a href="#bib-BCP47" class="bibref">
BCP47
</a>
</cite>
].
</p>
<p>
To
clear
the
default
language
for
a
subtree,
<code>
@language
</code>
can
be
set
to
<code>
null
</code>
in
a
<a href="#dfn-local-context" title="local-context" class="tref internalDFN">
local
context
</a>
as
follows:
</p>
<del class="diff-old">  {
  "@context": {
    ...
    "@language": "ja"
  },
  "name": "花澄",
  "details": {
    "@context": {
      "@language": null
    },
    "occupation": "Ninja"
  }
</del>
  <div class="example"><div class="example-title"><span>Example 28</span>: Clearing default language</div><pre class="example">{
<ins class="diff-chg">  "@context": {
    ...
    "@language": "ja"
  },
  "name": "花澄",
  "details": {
</ins><span class="diff">    "@context": {
<ins class="diff-chg">
      "@language": null
    }</span>,
    "occupation": "Ninja"
  }
</ins>
}
</pre>
</div>
<p>
Second,
it
is
possible
to
associate
a
language
with
a
specific
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
using
an
<a href="#dfn-expanded-term-definition" title="expanded-term-definition" class="tref internalDFN">
expanded
term
definition
</a>:
</p>
<del class="diff-old">  {
  "@context": {
    ...
    "ex": "http://example.com/vocab/",
    "@language": "ja",
    "name": { "@id": "ex:name",  },
    "occupation": { "@id": "ex:occupation" },
    "occupation_en": { "@id": "ex:occupation",  },
    "occupation_cs": { "@id": "ex:occupation",  }
  },
  "name": "Yagyū Muneyoshi",
  "occupation": "忍者",
  "occupation_en": "Ninja",
  "occupation_cs": "Nindža",
  ...
</del>
  <div class="example"><div class="example-title"><span>Example 29</span>: Expanded term definition with language</div><pre class="example">{
<ins class="diff-chg">  "@context": {
    ...
    "ex": "http://example.com/vocab/",
    "@language": "ja",
    "name": { "@id": "ex:name", <span class="diff">"@language": null</span> },
    "occupation": { "@id": "ex:occupation" },
    "occupation_en": { "@id": "ex:occupation", <span class="diff">"@language": "en"</span> },
    "occupation_cs": { "@id": "ex:occupation", <span class="diff">"@language": "cs"</span> }
  },
</ins>  <span class="diff">"name": "Yagyū Muneyoshi",
<ins class="diff-chg">
  "occupation": "忍者",
  "occupation_en": "Ninja",
  "occupation_cs": "Nindža",</span>
  ...
</ins>
}
</pre>
</div>
<p>
The
example
above
would
associate
<em>
忍者
</em>
with
the
specified
default
language
code
<code>
ja
</code>,
<em>
Ninja
</em>
with
the
language
code
<code>
en
</code>,
and
<em>
Nindža
</em>
with
the
language
code
<code>
cs
</code>.
The
value
of
<code>
name
</code>,
<em>
Yagyū
Muneyoshi
</em>
wouldn't
be
associated
with
any
language
code
since
<code>
@language
</code>
was
reset
to
<a href="#dfn-null" title="null" class="tref internalDFN">
null
</a>
in
the
<a href="#dfn-expanded-term-definition" title="expanded-term-definition" class="tref internalDFN">
expanded
term
definition
</a>.
</p>
<div class="note">
<div class="note-title">
<span>
Note
</span>
</div>
<p class="">
Language
associations
can
only
be
applied
to
plain
literal
<a href="#dfn-string" title="string" class="tref internalDFN">
strings
</a>.
<a href="#dfn-typed-value" title="typed-value" class="tref internalDFN">
Typed
values
</a>
or
values
that
are
subject
to
<a class="sec-ref" href="#type-coercion">
<span class="secno">
6.3
</span>
<span class="sec-title">
Type
Coercion
</span>
</a>
cannot
be
language
tagged.
</p>
</div>
<p>
Just
as
in
the
example
above,
systems
often
need
to
express
the
value
of
a
property
in
multiple
languages.
Typically,
such
systems
also
try
to
ensure
that
developers
have
a
programmatically
easy
way
to
navigate
the
data
structures
for
the
language-specific
data.
In
this
case,
<a href="#dfn-language-map" title="language-map" class="tref internalDFN">
language
maps
</a>
may
be
utilized.
</p>
<del class="diff-old">  {
  "@context":
  {
    ...
    "occupation": { "@id": "ex:occupation",  }
  },
  "name": "Yagyū Muneyoshi",
  "occupation":
  {
    "ja": "忍者",
    "en": "Ninja",
    "cs": "Nindža"
  }
  ...
</del>
  <div class="example"><div class="example-title"><span>Example 30</span>: Language map expressing a property in three languages</div><pre class="example">{
<ins class="diff-chg">  "@context":
  {
    ...
    "occupation": { "@id": "ex:occupation", <span class="diff">"@container": "@language"</span> }
  },
  "name": "Yagyū Muneyoshi",
  "occupation":
</ins>  <span class="diff">{
<ins class="diff-chg">
    "ja": "忍者",
    "en": "Ninja",
    "cs": "Nindža"
  }</span>
  ...
</ins>
}
</pre>
</div>
<p>
The
example
above
expresses
exactly
the
same
information
as
the
previous
example
but
consolidates
all
values
in
a
single
property.
To
access
the
value
in
a
specific
language
in
a
programming
language
supporting
dot-notation
accessors
for
object
properties,
a
developer
may
use
the
<code>
property.language
</code>
pattern.
For
example,
to
access
the
occupation
in
English,
a
developer
would
use
the
following
code
snippet:
<code>
obj.occupation.en
</code>.
</p>
<p>
Third,
it
is
possible
to
override
the
default
language
by
using
an
<a href="#dfn-expanded-value" title="expanded-value" class="tref internalDFN">
expanded
value
</a>:
</p>
<del class="diff-old">  {
  "@context": {
    ...
    "@language": "ja"
  },
  "name": "花澄",
  "occupation": {
    "@value": "Scientist",
    "@language": "en"
  }
</del>
  <div class="example"><div class="example-title"><span>Example 31</span>: Overriding default language using an expanded value</div><pre class="example">{
<ins class="diff-chg">  "@context": {
    ...
    "@language": "ja"
  },
  "name": "花澄",
  "occupation": <span class="diff">{
    "@value": "Scientist",
    "@language": "en"
  }</span>
</ins>
}
</pre>
</div>
<p>
This
makes
it
possible
to
specify
a
plain
string
by
omitting
the
<code>
@language
</code>
tag
or
setting
it
to
<code>
null
</code>
when
expressing
it
using
an
<a href="#dfn-expanded-value" title="expanded-value" class="tref internalDFN">
expanded
value
</a>:
</p>
<del class="diff-old">  {
  "@context": {
    ...
    "@language": "ja"
  },
  "name": {
    "@value": "Frank"
  },
  "occupation": {
    "@value": "Ninja",
    "@language": "en"
  },
  "speciality": "手裏剣"
</del>
  <div class="example"><div class="example-title"><span>Example 32</span>: Removing language information using an expanded value</div><pre class="example">{
<ins class="diff-chg">  "@context": {
    ...
    "@language": "ja"
  },
  "name": <span class="diff">{
    "@value": "Frank"
  }</span>,
  "occupation": {
    "@value": "Ninja",
    "@language": "en"
  },
  "speciality": "手裏剣"
</ins>
}
</pre>
</div>
</section>
<section id="overriding-vocab">
<h3>
<span class="secno">
<del class="diff-old">6.6
</del>
<ins class="diff-chg">6.7
</ins>
</span>
Overriding
@vocab
</h3>
<p>
If
<code>
@vocab
</code>
is
used
but
certain
keys
in
an
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
object
</a>
should
not
be
expanded
using
the
vocabulary
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
can
be
explicitly
set
to
<a href="#dfn-null" title="null" class="tref internalDFN">
null
</a>
in
the
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>.
For
instance,
in
the
example
below
the
<code>
databaseId
</code>
member
would
be
ignored
by
a
JSON-LD
processor.
</p>
<p>
</p>
<del class="diff-old">  {
  "@context":
  {
     "@vocab": "http://schema.org/",

  },
  "name": "Gregg Kellogg",

</del>
  <div class="example"><div class="example-title"><span>Example 33</span>: Using the null keyword to ignore data</div><pre class="example">{
<ins class="diff-chg">  "@context":
  {
     "@vocab": "http://schema.org/",
</ins>     <span class="diff">"databaseId": null</span>
<ins class="diff-chg">
  },
  "name": "Gregg Kellogg",
</ins>  <span class="diff">"databaseId": "23987520"</span>
}
</pre>
</div>
</section>
<section id="property-generators">
<h3>
<span class="secno">
<del class="diff-old">6.7
</del>
<ins class="diff-chg">6.8
</ins>
</span>
Property
Generators
</h3>
<p>
At
times,
an
author
may
find
that
they
need
to
express
the
same
value
for
multiple
properties.
The
simplest
approach
to
accomplish
this
goal
would
be
to
do
the
following:
</p>
<del class="diff-old">{
  "@context":
  {
    ,
    ,

  },
  "@id": "http://example.com/book",
  ,
  ,

</del>
<div class="example"><div class="example-title"><span>Example 34</span>: Verbose expression of multiple properties with the same value</div><pre class="example">{
<ins class="diff-chg">  "@context":
  {
</ins>    <span class="diff">"title1": "http://purl.org/dc/terms/title"</span>,
    <span class="diff">"title2": "http://schema.org/name"</span>,
    <span class="diff">"title3": "http://www.w3.org/2000/01/rdf-schema#label"</span>
<ins class="diff-chg">
  },
  "@id": "http://example.com/book",
</ins>  <span class="diff">"title1": "The Count of Monte Cristo"</span>,
  <span class="diff">"title2": "The Count of Monte Cristo"</span>,
  <span class="diff">"title3": "The Count of Monte Cristo"</span>
}
</pre>
</div>
<p>
Unfortunately,
the
approach
above
produces
redundant
data
and
would
become
a
publishing
burden
for
large
data
sets.
In
these
situations,
the
author
may
use
a
<dfn id="dfn-property-generator" title="property-generator">
property
generator
</dfn>
to
express
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
that
maps
to
multiple
<a href="#dfn-property" title="property" class="tref internalDFN">
properties
</a>
in
the
<a href="#dfn-json-ld-graph" title="json-ld-graph" class="tref internalDFN">
JSON-LD
graph
</a>.
This
method
can
be
accomplished
by
using
the
following
markup
pattern:
</p>
<del class="diff-old">{
  "@context":
  {
    "title": { "@id": [ "http://purl.org/dc/terms/title",
                        "http://schema.org/name",
                        "http://www.w3.org/2000/01/rdf-schema#label" ] }
  },
  "@id": "http://example.com/book",

</del>
<div class="example"><div class="example-title"><span>Example 35</span>: Generating multiple properties using a single term</div><pre class="example">{
<ins class="diff-chg">  "@context":
  {
</ins>    <span class="diff">"title": { "@id": [ "http://purl.org/dc/terms/title",
<ins class="diff-chg">
                        "http://schema.org/name",
                        "http://www.w3.org/2000/01/rdf-schema#label" ] }</span>
  },
  "@id": "http://example.com/book",
</ins>  <span class="diff">"title": "The Count of Monte Cristo"</span>
}
</pre>
</div>
<p>
While
the
term
above
is
only
used
once
outside
of
the
<code>
@context
</code>,
the
document
above
will
be
interpreted
like
so:
</p>
<table class="example">
<thead>
<tr>
<th>
Subject
</th>
<th>
Property
</th>
<th>
Value
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
http://example.com/book
</td>
<td>
http://purl.org/dc/terms/title
</td>
<td>
The
Count
of
Monte
Cristo
</td>
</tr>
<tr>
<td>
http://example.com/book
</td>
<td>
http://schema.org/name
</td>
<td>
The
Count
of
Monte
Cristo
</td>
</tr>
<tr>
<td>
http://example.com/book
</td>
<td>
http://www.w3.org/2000/01/rdf-schema#label
</td>
<td>
The
Count
of
Monte
Cristo
</td>
</tr>
</tbody>
</table>
</section>
<section id="iri-expansion-within-a-context">
<h3>
<span class="secno">
<del class="diff-old">6.8
</del>
<ins class="diff-chg">6.9
</ins>
</span>
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Expansion
Within
a
Context
</h3>
<p>
In
general,
normal
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
expansion
rules
apply
anywhere
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
is
expected
(see
<a class="sec-ref" href="#iris">
<span class="secno">
5.2
</span>
<span class="sec-title">
IRIs
</span>
</a>
).
Within
a
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
definition,
this
can
mean
that
terms
defined
within
the
context
may
also
be
used
within
that
context
as
long
as
there
are
no
circular
dependencies.
For
example,
it
is
common
to
use
the
<code>
xsd
</code>
namespace
when
defining
<a href="#dfn-typed-value" title="typed-value" class="tref internalDFN">
typed
value
</a>
s:
</p>
<del class="diff-old">{
  "@context":
  {
    ,
    "name": "http://xmlns.com/foaf/0.1/name",
    "age":
    {
      "@id": "http://xmlns.com/foaf/0.1/age",
      "@type":
    },
    "homepage":
    {
      "@id": "http://xmlns.com/foaf/0.1/homepage",
      "@type": "@id"
    }
  },
  ...
</del>
<div class="example"><div class="example-title"><span>Example 36</span>: IRI expansion within a context</div><pre class="example">{
<ins class="diff-chg">  "@context":
  {
</ins>    <span class="diff">"xsd": "http://www.w3.org/2001/XMLSchema#"</span>,
<ins class="diff-chg">
    "name": "http://xmlns.com/foaf/0.1/name",
    "age":
    {
      "@id": "http://xmlns.com/foaf/0.1/age",
      "@type": <span class="diff">"xsd:integer"</span>
    },
    "homepage":
    {
      "@id": "http://xmlns.com/foaf/0.1/homepage",
      "@type": "@id"
    }
  },
  ...
</ins>
}
</pre>
</div>
<p>
In
this
example,
the
<code>
xsd
</code>
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
is
defined
and
used
as
a
<a href="#dfn-prefix" title="prefix" class="tref internalDFN">
prefix
</a>
for
the
<code>
@type
</code>
coercion
of
the
<code>
age
</code>
property.
</p>
<p>
<a href="#dfn-term" title="term" class="tref internalDFN">
Terms
</a>
may
also
be
used
when
defining
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
of
another
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>:
</p>
<del class="diff-old">{
  "@context":
  {
    ,
    "xsd": "http://www.w3.org/2001/XMLSchema#",
    "name": ,
    "age":
    {
      "@id": ,
      "@type": "xsd:integer"
    },
    "homepage":
    {
      "@id": ,
      "@type": "@id"
    }
  },
  ...
</del>
<div class="example"><div class="example-title"><span>Example 37</span>: Using a term to define the IRI of another term within a context</div><pre class="example">{
<ins class="diff-chg">  "@context":
  {
</ins>    <span class="diff">"foaf": "http://xmlns.com/foaf/0.1/"</span>,
<ins class="diff-chg">
    "xsd": "http://www.w3.org/2001/XMLSchema#",
    "name": <span class="diff">"foaf:name"</span>,
    "age":
    {
      "@id": <span class="diff">"foaf:age"</span>,
      "@type": "xsd:integer"
    },
    "homepage":
    {
      "@id": <span class="diff">"foaf:homepage"</span>,
      "@type": "@id"
    }
  },
  ...
</ins>
}
</pre>
</div>
<p>
<a href="#dfn-compact-iri" title="compact-iri" class="tref internalDFN">
Compact
IRIs
</a>
and
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>
may
be
used
on
the
left-hand
side
of
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
definition.
</p>
<del class="diff-old">{
  "@context":
  {
    ,
    "xsd": "http://www.w3.org/2001/XMLSchema#",
    "name": "foaf:name",
    "":
    {
      "@type": "xsd:integer"
    },
    "":
    {
      "@type": "@id"
    }
  },
  ...
</del>
<div class="example"><div class="example-title"><span>Example 38</span>: Using a compact IRI as a term</div><pre class="example">{
<ins class="diff-chg">  "@context":
  {
</ins>    <span class="diff">"foaf": "http://xmlns.com/foaf/0.1/"</span>,
<ins class="diff-chg">
    "xsd": "http://www.w3.org/2001/XMLSchema#",
    "name": "foaf:name",
    "<span class="diff">foaf:age</span>":
    {
      "@type": "xsd:integer"
    },
    "<span class="diff">foaf:homepage</span>":
</ins>    <span class="diff">{
<ins class="diff-chg">
      "@type": "@id"
    }</span>
  },
  ...
</ins>
}
</pre>
</div>
<p>
In
this
example,
the
<a href="#dfn-compact-iri" title="compact-iri" class="tref internalDFN">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
form
is
used
in
two
different
ways.
In
the
first
approach,
<code>
foaf:age
</code>
declares
both
the
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
for
the
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
(using
short-form)
as
well
as
the
<code>
@type
</code>
associated
with
the
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>.
In
the
second
approach,
only
the
<code>
@type
</code>
associated
with
the
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
is
specified.
The
full
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
for
<code>
foaf:homepage
</code>
is
determined
by
looking
up
the
<code>
foaf
</code>
<a href="#dfn-prefix" title="prefix" class="tref internalDFN">
prefix
</a>
in
the
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>.
</p>
<p>
<a href="#dfn-absolute-iri" title="absolute-iri" class="tref internalDFN">
Absolute
IRIs
</a>
may
also
be
used
in
the
key
position
in
a
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>:
</p>
<del class="diff-old">{
  "@context":
  {
    "foaf": "http://xmlns.com/foaf/0.1/",
    "xsd": "http://www.w3.org/2001/XMLSchema#",
    "name": "foaf:name",
    "foaf:age":
    {
      "@id": "foaf:age",
      "@type": "xsd:integer"
    },
    "":
    {
      "@type": "@id"
    }
  },
  ...
</del>
<div class="example"><div class="example-title"><span>Example 39</span>: Associating context definitions with absolute IRIs</div><pre class="example">{
<ins class="diff-chg">  "@context":
  {
    "foaf": "http://xmlns.com/foaf/0.1/",
    "xsd": "http://www.w3.org/2001/XMLSchema#",
    "name": "foaf:name",
    "foaf:age":
    {
      "@id": "foaf:age",
      "@type": "xsd:integer"
    },
    "<span class="diff">http://xmlns.com/foaf/0.1/homepage</span>":
    {
      "@type": "@id"
    }
  },
  ...
</ins>
}
</pre>
</div>
<p>
In
order
for
the
<a href="#dfn-absolute-iri" title="absolute-iri" class="tref internalDFN">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
to
match
above,
the
<a href="#dfn-absolute-iri" title="absolute-iri" class="tref internalDFN">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
needs
to
be
used
in
the
<a href="#dfn-json-ld-document" title="json-ld-document" class="tref internalDFN">
JSON-LD
document
</a>.
Also
note
that
<code>
foaf:homepage
</code>
will
not
use
the
<code>
{
"@type":
"@id"
}
</code>
declaration
because
<code>
foaf:homepage
</code>
is
not
the
same
as
<code>
http://xmlns.com/foaf/0.1/homepage
</code>.
That
is,
<a href="#dfn-term" title="term" class="tref internalDFN">
terms
</a>
are
looked
up
in
a
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
using
direct
string
comparison
before
the
<a href="#dfn-prefix" title="prefix" class="tref internalDFN">
prefix
</a>
lookup
mechanism
is
applied.
</p>
<div class="note">
<div class="note-title">
<span>
<ins class="diff-new">Note
</ins></span></div><p class=""><ins class="diff-new">
While
it
is
possible
to
define
a
</ins><a href="#dfn-compact-iri" title="compact-iri" class="tref internalDFN"><ins class="diff-new">
compact
</ins><abbr title="Internationalized Resource Identifier"><ins class="diff-new">
IRI
</ins></abbr></a>,<ins class="diff-new">
or
an
</ins><a href="#dfn-absolute-iri" title="absolute-iri" class="tref internalDFN"><ins class="diff-new">
absolute
</ins><abbr title="Internationalized Resource Identifier"><ins class="diff-new">
IRI
</ins></abbr></a><ins class="diff-new">
to
expand
to
some
other
unrelated
</ins><a href="#dfn-iri" title="iri" class="tref internalDFN"><abbr title="Internationalized Resource Identifier"><ins class="diff-new">
IRI
</ins></abbr></a><ins class="diff-new">
(for
example,
</ins><code><ins class="diff-new">
foaf:name
</ins></code><ins class="diff-new">
expanding
to
</ins><code><ins class="diff-new">
http://example.org/unrelated#species
</ins></code><ins class="diff-new">
),
such
usage
is
strongly
discouraged.
</ins></p></div>
<p>
The
only
exception
for
using
terms
in
the
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
is
that
circular
definitions
are
not
allowed.
That
is,
a
definition
of
<em>
term1
</em>
cannot
depend
on
the
definition
of
<em>
term2
</em>
if
<em>
term2
</em>
also
depends
on
<em>
term1
</em>.
For
example,
the
following
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
definition
is
illegal:
</p>
<del class="diff-old">{
  "@context":
  {
    "term1": "term2:foo",
    "term2": "term1:bar"
  },
  ...
</del>
<div class="example"><div class="example-title"><span>Example 40</span>: Illegal circular definition of terms within a context</div><pre class="example">{
<ins class="diff-chg">  "@context":
  {
</ins>    <span class="diff">"term1": "term2:foo",
<ins class="diff-chg">
    "term2": "term1:bar"</span>
  },
  ...
</ins>
}
</pre>
</div>
</section>
<section id="sets-and-lists">
<h3>
<span class="secno">
<del class="diff-old">6.9
</del>
<ins class="diff-chg">6.10
</ins>
</span>
Sets
and
Lists
</h3>
<p>
A
JSON-LD
author
can
express
multiple
values
in
a
compact
way
by
using
<a href="#dfn-array" title="array" class="tref internalDFN">
arrays
</a>.
Since
graphs
do
not
describe
ordering
for
links
between
nodes,
arrays
in
JSON-LD
do
not
provide
an
ordering
of
the
contained
elements
by
default.
This
is
exactly
the
opposite
from
regular
JSON
arrays,
which
are
ordered
by
default.
For
example,
consider
the
following
simple
document:
</p>
<del class="diff-old">{
...
  "@id": "http://example.org/people#joebob",
  "nick": ,
...
</del>
<div class="example"><div class="example-title"><span>Example 41</span>: Multiple values with no inherent order</div><pre class="example">{
<ins class="diff-chg">...
  "@id": "http://example.org/people#joebob",
  "nick": <span class="diff">[ "joe", "bob", "JB" ]</span>,
...
</ins>
}
</pre>
</div>
<p>
The
markup
shown
above
would
result
in
the
following
data
being
generated,
each
relating
the
node
to
an
individual
value,
with
no
inherent
order:
</p>
<table class="example">
<thead>
<tr>
<th>
Subject
</th>
<th>
Property
</th>
<th>
Value
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
http://example.org/people#joebob
</td>
<td>
http://xmlns.com/foaf/0.1/nick
</td>
<td>
joe
</td>
</tr>
<tr>
<td>
http://example.org/people#joebob
</td>
<td>
http://xmlns.com/foaf/0.1/nick
</td>
<td>
bob
</td>
</tr>
<tr>
<td>
http://example.org/people#joebob
</td>
<td>
http://xmlns.com/foaf/0.1/nick
</td>
<td>
JB
</td>
</tr>
</tbody>
</table>
<p>
Multiple
values
may
also
be
expressed
using
the
expanded
form:
</p>
<del class="diff-old">{
  "@id": "http://example.org/articles/8",
  "dc:title":
  [
    {
      "@value": "Das Kapital",
      "@language": "de"
    },
    {
      "@value": "Capital",
      "@language": "en"
    }
  ]
</del>
<div class="example"><div class="example-title"><span>Example 42</span>: Using an expanded form to set multiple values</div><pre class="example">{
<ins class="diff-chg">  "@id": "http://example.org/articles/8",
  "dc:title": <span class="diff">
  [
    {
      "@value": "Das Kapital",
      "@language": "de"
    },
    {
      "@value": "Capital",
      "@language": "en"
    }
  ]</span>
</ins>
}
</pre>
</div>
<p>
The
markup
shown
above
would
generate
the
following
data,
again
with
no
inherent
order:
</p>
<table class="example">
<thead>
<tr>
<th>
Subject
</th>
<th>
Property
</th>
<th>
Value
</th>
<th>
Language
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
http://example.org/articles/8
</td>
<td>
http://purl.org/dc/terms/title
</td>
<td>
Das
Kapital
</td>
<td>
de
</td>
</tr>
<tr>
<td>
http://example.org/articles/8
</td>
<td>
http://purl.org/dc/terms/title
</td>
<td>
Capital
</td>
<td>
en
</td>
</tr>
</tbody>
</table>
<p>
As
the
notion
of
ordered
collections
is
rather
important
in
data
modeling,
it
is
useful
to
have
specific
language
support.
In
JSON-LD,
a
list
may
be
represented
using
the
<code>
@list
</code>
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keyword
</a>
as
follows:
</p>
<del class="diff-old">{
...
  "@id": "http://example.org/people#joebob",
  "foaf:nick":
  {
    "@list": [ "joe", "bob", "jaybee" ]
  },
...
</del>
<div class="example"><div class="example-title"><span>Example 43</span>: An ordered collection of values in JSON-LD</div><pre class="example">{
<ins class="diff-chg">...
  "@id": "http://example.org/people#joebob",
  "foaf:nick":
</ins>  <span class="diff">{
<ins class="diff-chg">
    "@list": [ "joe", "bob", "jaybee" ]
  }</span>,
...
</ins>
}
</pre>
</div>
<p>
This
describes
the
use
of
this
<a href="#dfn-array" title="array" class="tref internalDFN">
array
</a>
as
being
ordered,
and
order
is
maintained
when
processing
a
document.
If
every
use
of
a
given
multi-valued
property
is
a
list,
this
may
be
abbreviated
by
setting
<code>
@container
</code>
to
<code>
@list
</code>
in
the
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>:
</p>
<del class="diff-old">{
  "@context":
  {
    ...
    "nick":
    {
      "@id": "http://xmlns.com/foaf/0.1/nick",
      "@container": "@list"
    }
  },
...
  "@id": "http://example.org/people#joebob",
  "nick": ,
...
</del>
<div class="example"><div class="example-title"><span>Example 44</span>: Specifying that a collection is ordered in the context</div><pre class="example">{
  <span class="diff">"@context":
<ins class="diff-chg">  {
    ...
    "nick":
    {
      "@id": "http://xmlns.com/foaf/0.1/nick",
      "@container": "@list"
    }
  }</span>,
...
  "@id": "http://example.org/people#joebob",
  "nick": <span class="diff">[ "joe", "bob", "jaybee" ]</span>,
...
</ins>
}
</pre>
</div>
<div class="note">
<div class="note-title">
<span>
Note
</span>
</div>
<p class="">
List
of
lists
are
not
allowed
in
this
version
of
JSON-LD.
This
decision
was
made
due
to
the
extreme
amount
of
added
complexity
when
processing
lists
of
lists.
</p>
</div>
<p>
While
<code>
@list
</code>
is
used
to
describe
<em>
ordered
<del class="diff-old">sets
</del>
<ins class="diff-chg">lists
</ins>
</em>,
the
<code>
@set
</code>
keyword
is
used
to
describe
<em>
unordered
sets
</em>.
The
use
of
<code>
@set
</code>
in
the
body
of
a
JSON-LD
document
is
optimized
away
when
processing
the
document,
as
it
is
just
syntactic
sugar.
However,
<code>
@set
</code>
is
helpful
when
used
within
the
context
of
a
document.
Values
of
terms
associated
with
a
<code>
@set
</code>
or
<code>
@list
</code>
container
are
always
represented
in
the
form
of
an
<a href="#dfn-array" title="array" class="tref internalDFN">
array
</a>,
even
if
there
is
just
a
single
value
that
would
otherwise
be
optimized
to
a
non-array
form
in
compact
form
(see
<a class="sec-ref" href="#compact-document-form">
<span class="secno">
<del class="diff-old">6.15
</del>
<ins class="diff-chg">6.16
</ins>
</span>
<span class="sec-title">
Compact
Document
Form
</span>
</a>
).
This
makes
post-processing
of
JSON-LD
documents
easier
as
the
data
is
always
in
array
form,
even
if
the
array
only
contains
a
single
value.
</p>
<div class="note">
<div class="note-title">
<span>
Note
</span>
</div>
<p class="">
The
use
of
<code>
@container
</code>
in
the
body
of
a
JSON-LD
document
has
no
meaning
and
is
not
allowed
by
the
JSON-LD
grammar
(see
<a class="sec-ref" href="#json-ld-grammar">
<span class="secno">
B.
</span>
<span class="sec-title">
JSON-LD
Grammar
</span>
</a>
).
</p>
</div>
</section>
<section id="embedding">
<h3>
<span class="secno">
<del class="diff-old">6.10
</del>
<ins class="diff-chg">6.11
</ins>
</span>
Embedding
</h3>
<p>
<dfn id="dfn-embedding" title="embedding">
Embedding
</dfn>
is
a
JSON-LD
feature
that
allows
an
author
to
use
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
objects
</a>
as
<a href="#dfn-property" title="property" class="tref internalDFN">
property
</a>
values.
This
is
a
commonly
used
mechanism
for
creating
a
parent-child
relationship
between
two
<a href="#dfn-node" title="node" class="tref internalDFN">
nodes
</a>.
</p>
<p>
The
example
shows
two
nodes
related
by
a
property
from
the
first
node:
</p>
<del class="diff-old">  {
...
  "name": "Manu Sporny",
  "":
  {
    "",
    "",
  }
...
</del>
  <div class="example"><div class="example-title"><span>Example 45</span>: Embedding a node object as property value of another node object</div><pre class="example">{
<ins class="diff-chg">...
  "name": "Manu Sporny",
  "<span class="diff">knows</span>":
  {
    "<span class="diff">@type</span>": "<span class="diff">Person</span>",
    "<span class="diff">name</span>": "<span class="diff">Gregg Kellogg</span>",
  }
...
</ins>
}
</pre>
</div>
<p>
A
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
object
</a>,
like
the
one
used
above,
may
be
used
in
any
value
position
in
the
body
of
a
JSON-LD
document.
</p>
</section>
<section id="named-graphs">
<h3>
<span class="secno">
<del class="diff-old">6.11
</del>
<ins class="diff-chg">6.12
</ins>
</span>
Named
Graphs
</h3>
<p>
At
times,
it
is
necessary
to
make
statements
about
a
<a href="#dfn-json-ld-graph" title="json-ld-graph" class="tref internalDFN">
JSON-LD
graph
</a>
itself,
rather
than
just
a
single
<a href="#dfn-node" title="node" class="tref internalDFN">
node
</a>.
This
can
be
done
by
grouping
a
set
of
<a href="#dfn-node" title="node" class="tref internalDFN">
nodes
</a>
using
the
<code>
@graph
</code>
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keyword
</a>.
A
developer
may
also
name
data
expressed
using
the
<code>
@graph
</code>
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keyword
</a>
by
pairing
it
with
an
<code>
@id
</code>
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keyword
</a>
as
shown
in
the
following
example:
</p>
<del class="diff-old">  {
  "@context": {
    "generatedAt": "http://www.w3.org/ns/prov#generatedAtTime",
    "Person": "http://xmlns.com/foaf/0.1/Person",
    "name": "http://xmlns.com/foaf/0.1/name",
    "knows": "http://xmlns.com/foaf/0.1/knows",
    "xsd": "http://www.w3.org/2001/XMLSchema#"
  },
  "@id": "http://example.org/graphs/73",
  "generatedAt": { "@value": "2012-04-09", "@type": "xsd:date" },
  "@graph":
  [
    {
      "@id": "http://manu.sporny.org/i/public",
      "@type": "Person",
      "name": "Manu Sporny",
      "knows": "http://greggkellogg.net/foaf#me"
    },
    {
      "@id": "http://greggkellogg.net/foaf#me",
      "@type": "Person",
      "name": "Gregg Kellogg",
      "knows": "http://manu.sporny.org/i/public"
    }
  ]
</del>
  <div class="example"><div class="example-title"><span>Example 46</span>: Identifying and making statements about a graph</div><pre class="example">{
<ins class="diff-chg">  "@context": {
    "generatedAt": "http://www.w3.org/ns/prov#generatedAtTime",
    "Person": "http://xmlns.com/foaf/0.1/Person",
    "name": "http://xmlns.com/foaf/0.1/name",
    "knows": "http://xmlns.com/foaf/0.1/knows",
    "xsd": "http://www.w3.org/2001/XMLSchema#"
  },
</ins>  <span class="diff">"@id": "http://example.org/graphs/73",
<ins class="diff-chg">
  "generatedAt": { "@value": "2012-04-09", "@type": "xsd:date" },
  "@graph":</span>
  [
    {
      "@id": "http://manu.sporny.org/i/public",
      "@type": "Person",
      "name": "Manu Sporny",
      "knows": "http://greggkellogg.net/foaf#me"
    },
    {
      "@id": "http://greggkellogg.net/foaf#me",
      "@type": "Person",
      "name": "Gregg Kellogg",
      "knows": "http://manu.sporny.org/i/public"
    }
  ]
</ins>
}
</pre>
</div>
<p>
The
example
above
expresses
a
<em>
named
</em>
<a href="#dfn-json-ld-graph" title="json-ld-graph" class="tref internalDFN">
JSON-LD
graph
</a>
that
is
identified
by
the
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
<code>
http://example.org/graphs/73
</code>.
That
graph
is
composed
of
the
statements
about
Manu
and
Gregg.
Metadata
about
the
graph
itself
is
also
expressed
via
the
<code>
generatedAt
</code>
property,
which
specifies
when
the
graph
was
generated.
An
alternative
view
of
the
information
above
is
represented
in
table
form
below:
</p>
<table class="example">
<thead>
<tr>
<th>
Graph
</th>
<th>
Subject
</th>
<th>
Property
</th>
<th>
Value
</th>
<th>
Value
Type
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
http://example.org/graphs/73
</td>
<td>
http://example.org/graphs/73
</td>
<td>
http://www.w3.org/ns/prov#generatedAtTime
</td>
<td>
2012-04-09
</td>
<td>
http://www.w3.org/2001/XMLSchema#date
</td>
</tr>
<tr>
<td>
http://example.org/graphs/73
</td>
<td>
http://manu.sporny.org/i/public
</td>
<td>
http://www.w3.org/2001/XMLSchema#type
</td>
<td>
http://xmlns.com/foaf/0.1/Person
</td>
<td>
</td>
</tr>
<tr>
<td>
http://example.org/graphs/73
</td>
<td>
http://manu.sporny.org/i/public
</td>
<td>
http://xmlns.com/foaf/0.1/name
</td>
<td>
Manu
Sporny
</td>
<td>
</td>
</tr>
<tr>
<td>
http://example.org/graphs/73
</td>
<td>
http://manu.sporny.org/i/public
</td>
<td>
http://xmlns.com/foaf/0.1/knows
</td>
<td>
http://greggkellogg.net/foaf#me
</td>
<td>
</td>
</tr>
<tr>
<td>
http://example.org/graphs/73
</td>
<td>
http://greggkellogg.net/foaf#me
</td>
<td>
http://www.w3.org/2001/XMLSchema#type
</td>
<td>
http://xmlns.com/foaf/0.1/Person
</td>
<td>
</td>
</tr>
<tr>
<td>
http://example.org/graphs/73
</td>
<td>
http://greggkellogg.net/foaf#me
</td>
<td>
http://xmlns.com/foaf/0.1/name
</td>
<td>
Gregg
Kellogg
</td>
<td>
</td>
</tr>
<tr>
<td>
http://example.org/graphs/73
</td>
<td>
http://greggkellogg.net/foaf#me
</td>
<td>
http://xmlns.com/foaf/0.1/knows
</td>
<td>
http://manu.sporny.org/i/public
</td>
<td>
</td>
</tr>
</tbody>
</table>
<p>
When
<del class="diff-old">@graph
is
used
in
</del>
a
<ins class="diff-new">JSON-LD
</ins>
document's
top-level
<ins class="diff-new">structure
is
an
</ins><a href="#dfn-json-object" title="json-object" class="tref internalDFN">
object
<del class="diff-old">which
has
</del>
</a>
<ins class="diff-chg">that
contains
</ins>
no
other
<a href="#dfn-property" title="property" class="tref internalDFN">
properties
</a>
<ins class="diff-new">than
</ins><code><ins class="diff-new">
@graph
</ins></code><ins class="diff-new">
and
optionally
</ins><code><ins class="diff-new">
@context
</ins></code><ins class="diff-new">
(properties
</ins>
that
are
<ins class="diff-new">not
</ins>
mapped
to
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
or
a
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keyword
</a>
<del class="diff-old">it
</del>
<ins class="diff-chg">are
ignored),
</ins><code><ins class="diff-chg">
@graph
</ins></code>
is
considered
to
express
the
otherwise
implicit
<a href="#dfn-default-graph" title="default-graph" class="tref internalDFN">
default
<del class="diff-old">graph.
</del>
<ins class="diff-chg">graph
</ins></a>.
This
mechanism
can
be
useful
when
a
number
of
<a href="#dfn-node" title="node" class="tref internalDFN">
nodes
</a>
<del class="diff-old">do
not
directly
relate
to
one
another
through
a
property
or
where
embedding
</del>
<ins class="diff-chg">exist
at
the
document's
top
level
that
share
the
same
</ins><a href="#dfn-context" title="context" class="tref internalDFN"><ins class="diff-chg">
context
</ins></a>.<ins class="diff-chg">
The
</ins><code><ins class="diff-chg">
@graph
</ins></code><ins class="diff-chg">
keyword
collects
such
nodes
in
an
</ins><a href="#dfn-array" title="array" class="tref internalDFN"><ins class="diff-chg">
array
</ins>
</a>
<del class="diff-old">is
not
desirable
to
</del>
<ins class="diff-chg">and
allows
</ins>
the
<del class="diff-old">application.
For
example:
</del>
<ins class="diff-chg">use
of
a
shared
context.
</ins>
</p>
<del class="diff-old">  {
  "@context": ...,
  "":
  [
    {
      "@id": "http://manu.sporny.org/i/public",
      "@type": "foaf:Person",
      "name": "Manu Sporny",
      "knows": "http://greggkellogg.net/foaf#me"
    },
    {
      "@id": "http://greggkellogg.net/foaf#me",
      "@type": "foaf:Person",
      "name": "Gregg Kellogg",
      "knows": "http://manu.sporny.org/i/public"
    }
  ]
</del>
  <div class="example"><div class="example-title"><span>Example 47</span>: Using @graph to explicitly express the default graph</div><pre class="example">{
<ins class="diff-chg">  "@context": ...,
  "<span class="diff">@graph</span>":
  [
    {
      "@id": "http://manu.sporny.org/i/public",
      "@type": "foaf:Person",
      "name": "Manu Sporny",
      "knows": "http://greggkellogg.net/foaf#me"
    },
    {
      "@id": "http://greggkellogg.net/foaf#me",
      "@type": "foaf:Person",
      "name": "Gregg Kellogg",
      "knows": "http://manu.sporny.org/i/public"
    }
  ]
</ins>
}
</pre>
</div>
<p>
In
this
case,
embedding
doesn't
work
as
each
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
object
</a>
references
the
other.
<del class="diff-old">Using
the
@graph
keyword
allows
multiple
nodes
to
be
defined
within
an
array
,
and
allows
the
use
of
a
shared
context
.
</del>
This
is
equivalent
to
using
multiple
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
objects
</a>
in
array
and
defining
the
<code>
@context
</code>
within
each
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
object
</a>:
</p>
<del class="diff-old">  [
  {

    "@id": "http://manu.sporny.org/i/public",
    "@type": "foaf:Person",
    "name": "Manu Sporny",
    "knows": "http://greggkellogg.net/foaf#me"
  },
  {

    "@id": "http://greggkellogg.net/foaf#me",
    "@type": "foaf:Person",
    "name": "Gregg Kellogg",
    "knows": "http://manu.sporny.org/i/public"
  }
</del>
  <div class="example"><div class="example-title"><span>Example 48</span>: Context needs to be duplicated if @graph is not used</div><pre class="example">[
<ins class="diff-chg">  {
</ins>    <span class="diff">"@context": ...,</span>
<ins class="diff-chg">
    "@id": "http://manu.sporny.org/i/public",
    "@type": "foaf:Person",
    "name": "Manu Sporny",
    "knows": "http://greggkellogg.net/foaf#me"
  },
  {
</ins>    <span class="diff">"@context": ...,</span>
<ins class="diff-chg">
    "@id": "http://greggkellogg.net/foaf#me",
    "@type": "foaf:Person",
    "name": "Gregg Kellogg",
    "knows": "http://manu.sporny.org/i/public"
  }
</ins>
]
</pre>
</div>
</section>
<section id="identifying-blank-nodes">
<h3>
<span class="secno">
<del class="diff-old">6.12
</del>
<ins class="diff-chg">6.13
</ins>
</span>
Identifying
Blank
Nodes
</h3>
<p>
At
times,
it
becomes
necessary
to
be
able
to
express
information
without
being
able
to
uniquely
identify
the
<a href="#dfn-node" title="node" class="tref internalDFN">
node
</a>.
This
type
of
node
is
called
a
<a href="#dfn-blank-node" title="blank-node" class="tref internalDFN">
blank
node
</a>
(see
<cite>
<a href="http://www.w3.org/TR/rdf11-concepts/#section-blank-nodes">
Section
3.4:
Blank
Nodes
</a>
</cite>
of
[
<cite>
<a href="#bib-RDF-CONCEPTS" class="bibref">
RDF-CONCEPTS
</a>
</cite>
]).
In
JSON-LD,
<a href="#dfn-blank-node-identifier" title="blank-node-identifier" class="tref internalDFN">
blank
node
identifiers
</a>
are
automatically
created
if
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
is
not
specified
using
the
<code>
@id
</code>
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keyword
</a>.
However,
authors
may
provide
identifiers
for
<a href="#dfn-blank-node" title="blank-node" class="tref internalDFN">
blank
nodes
</a>
by
using
the
special
<code>
_
</code>
(underscore)
<a href="#dfn-prefix" title="prefix" class="tref internalDFN">
prefix
</a>.
This
allows
one
to
reference
the
node
locally
within
the
document,
but
makes
it
impossible
to
reference
the
node
from
an
external
document.
The
<a href="#dfn-blank-node-identifier" title="blank-node-identifier" class="tref internalDFN">
blank
node
identifier
</a>
is
scoped
to
the
document
in
which
it
is
used.
</p>
<del class="diff-old">  {
...
  "@id": "",
...
</del>
  <div class="example"><div class="example-title"><span>Example 49</span>: Specifying a local blank node identifier</div><pre class="example">{
<ins class="diff-chg">...
  "@id": "<span class="diff">_:foo</span>",
...
</ins>
}
</pre>
</div>
<p>
The
example
above
would
set
the
node
to
<code>
_:foo
</code>,
which
can
then
be
used
elsewhere
in
the
JSON-LD
document
to
refer
back
to
the
<a href="#dfn-blank-node" title="blank-node" class="tref internalDFN">
blank
node
</a>.
If
a
developer
finds
that
they
refer
to
the
<a href="#dfn-blank-node" title="blank-node" class="tref internalDFN">
blank
node
</a>
more
than
once,
they
should
consider
naming
the
node
using
a
dereferenceable
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
so
that
it
can
also
be
referenced
from
other
documents.
</p>
</section>
<section id="aliasing-keywords">
<h3>
<span class="secno">
<del class="diff-old">6.13
</del>
<ins class="diff-chg">6.14
</ins>
</span>
Aliasing
Keywords
</h3>
<p>
Each
of
the
JSON-LD
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keywords
</a>,
except
for
<code>
@context
</code>,
may
be
aliased
to
application-specific
keywords.
This
feature
allows
legacy
JSON
content
to
be
utilized
by
JSON-LD
by
re-using
JSON
keys
that
already
exist
in
legacy
documents.
This
feature
also
allows
developers
to
design
domain-specific
implementations
using
only
the
JSON-LD
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>.
</p>
<del class="diff-old">  {
  "@context":
  {
     ,
     ,
     "name": "http://xmlns.com/foaf/0.1/name"
  },
  "": "http://example.com/about#gregg",
  "": "http://xmlns.com/foaf/0.1/Person",
  "name": "Gregg Kellogg"
</del>
  <div class="example"><div class="example-title"><span>Example 50</span>: Aliasing keywords</div><pre class="example">{
<ins class="diff-chg">  "@context":
  {
</ins>     <span class="diff">"url": "@id"</span>,
     <span class="diff">"a": "@type"</span>,
<ins class="diff-chg">
     "name": "http://xmlns.com/foaf/0.1/name"
  },
  "<span class="diff">url</span>": "http://example.com/about#gregg",
  "<span class="diff">a</span>": "http://xmlns.com/foaf/0.1/Person",
  "name": "Gregg Kellogg"
</ins>
}
</pre>
</div>
<p>
In
the
example
above,
the
<code>
@id
</code>
and
<code>
@type
</code>
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keywords
</a>
have
been
given
the
aliases
<strong>
url
</strong>
and
<strong>
a
</strong>,
respectively.
</p>
<p>
Since
keywords
cannot
be
redefined,
they
can
also
not
be
aliased
to
other
keywords.
Every
statement
in
the
context
having
a
keyword
as
the
key
(as
in
<code style="white-space: nowrap">
{
"@type":
...
}
</code>
)
will
be
ignored
when
being
processed.
</p>
</section>
<section id="expanded-document-form">
<h3>
<span class="secno">
<del class="diff-old">6.14
</del>
<ins class="diff-chg">6.15
</ins>
</span>
Expanded
Document
Form
</h3>
<p>
The
JSON-LD
Algorithms
and
API
specification
[
<cite>
<a href="#bib-JSON-LD-API" class="bibref">
JSON-LD-API
</a>
</cite>
]
defines
a
method
for
<em>
expanding
</em>
a
JSON-LD
document.
Expansion
is
the
process
of
taking
a
JSON-LD
document
and
applying
a
<code>
@context
</code>
such
that
all
IRIs,
types,
and
values
are
expanded
so
that
the
<code>
@context
</code>
is
no
longer
necessary.
</p>
<p>
For
example,
assume
the
following
JSON-LD
input
document:
</p>
<del class="diff-old">{
   "@context":
   {
      "name": "http://xmlns.com/foaf/0.1/name",
      "homepage": {
        "@id": "http://xmlns.com/foaf/0.1/homepage",
        "@type": "@id"
      }
   },
   "name": "Manu Sporny",
   "homepage": "http://manu.sporny.org/"
</del>
<div class="example"><div class="example-title"><span>Example 51</span>: Sample JSON-LD document</div><pre class="example">{
<ins class="diff-chg">   "@context":
   {
      "name": "http://xmlns.com/foaf/0.1/name",
      "homepage": {
        "@id": "http://xmlns.com/foaf/0.1/homepage",
        "@type": "@id"
      }
   },
   "name": "Manu Sporny",
   "homepage": "http://manu.sporny.org/"
</ins>
}
</pre>
</div>
<p>
Running
the
JSON-LD
Expansion
algorithm
against
the
JSON-LD
input
document
provided
above
would
result
in
the
following
output:
</p>
<del class="diff-old">[
  {
    "http://xmlns.com/foaf/0.1/name": [
      { "@value": "Manu Sporny" }
    ],
    "http://xmlns.com/foaf/0.1/homepage": [
      { "@id": "http://manu.sporny.org/" }
    ]
  }
</del>
<div class="example"><div class="example-title"><span>Example 52</span>: Expanded form for the previous example</div><pre class="example">[
<ins class="diff-chg">  {
    "http://xmlns.com/foaf/0.1/name": [
      { "@value": "Manu Sporny" }
    ],
    "http://xmlns.com/foaf/0.1/homepage": [
      { "@id": "http://manu.sporny.org/" }
    ]
  }
</ins>
]
</pre>
</div>
<p>
Expanded
document
form
is
useful
when
an
application
has
to
process
input
data
in
a
deterministic
form.
It
has
been
optimized
to
ensure
that
the
code
that
developers
have
to
write
is
minimized
compared
to
the
code
that
would
have
to
be
written
to
operate
on
<a class="sec-ref" href="#compact-document-form">
<span class="secno">
<del class="diff-old">6.15
</del>
<ins class="diff-chg">6.16
</ins>
</span>
<span class="sec-title">
Compact
Document
Form
</span>
</a>.
</p>
</section>
<section id="compact-document-form">
<h3>
<span class="secno">
<del class="diff-old">6.15
</del>
<ins class="diff-chg">6.16
</ins>
</span>
Compact
Document
Form
</h3>
<p>
The
JSON-LD
Algorithms
and
API
specification
[
<cite>
<a href="#bib-JSON-LD-API" class="bibref">
JSON-LD-API
</a>
</cite>
]
defines
a
method
for
<em>
compacting
</em>
a
JSON-LD
document.
Compaction
is
the
process
of
taking
a
JSON-LD
document
and
applying
a
context
such
that
a
very
compact
form
of
the
document
is
generated.
At
times,
a
JSON-LD
document
may
be
received
that
is
not
in
its
most
compact
form.
The
JSON-LD
Algorithms,
via
an
API,
provides
a
way
to
compact
a
JSON-LD
document.
</p>
<p>
For
example,
assume
the
following
JSON-LD
input
document:
</p>
<del class="diff-old">[
  {
    "http://xmlns.com/foaf/0.1/name": [ "Manu Sporny" ],
    "http://xmlns.com/foaf/0.1/homepage": [
      {
       "@id": "http://manu.sporny.org/"
      }
    ]
  }
</del>
<div class="example"><div class="example-title"><span>Example 53</span>: Sample expanded JSON-LD document</div><pre class="example">[
<ins class="diff-chg">  {
    "http://xmlns.com/foaf/0.1/name": [ "Manu Sporny" ],
    "http://xmlns.com/foaf/0.1/homepage": [
      {
       "@id": "http://manu.sporny.org/"
      }
    ]
  }
</ins>
]
</pre>
</div>
<p>
Additionally,
assume
the
following
developer-supplied
JSON-LD
context:
</p>
<del class="diff-old">{
  "@context": {
    "name": "http://xmlns.com/foaf/0.1/name",
    "homepage": {
      "@id": "http://xmlns.com/foaf/0.1/homepage",
      "@type": "@id"
    }
  }
</del>
<div class="example"><div class="example-title"><span>Example 54</span>: Sample context</div><pre class="example">{
<ins class="diff-chg">  "@context": {
    "name": "http://xmlns.com/foaf/0.1/name",
    "homepage": {
      "@id": "http://xmlns.com/foaf/0.1/homepage",
      "@type": "@id"
    }
  }
</ins>
}
</pre>
</div>
<p>
Running
the
JSON-LD
Compaction
algorithm
given
the
context
supplied
above
against
the
JSON-LD
input
document
provided
above
would
result
in
the
following
output:
</p>
<del class="diff-old">{
  "@context": {
    "name": "http://xmlns.com/foaf/0.1/name",
    "homepage": {
      "@id": "http://xmlns.com/foaf/0.1/homepage",
      "@type": "@id"
    }
  },
  "name": "Manu Sporny",
  "homepage": "http://manu.sporny.org/"
</del>
<div class="example"><div class="example-title"><span>Example 55</span>: Compact form of the sample document once sample context has been applied</div><pre class="example">{
<ins class="diff-chg">  "@context": {
    "name": "http://xmlns.com/foaf/0.1/name",
    "homepage": {
      "@id": "http://xmlns.com/foaf/0.1/homepage",
      "@type": "@id"
    }
  },
  "name": "Manu Sporny",
  "homepage": "http://manu.sporny.org/"
</ins>
}
</pre>
</div>
<p>
The
compaction
algorithm
enables
a
developer
to
map
any
document
into
an
application-specific
compacted
form.
The
process
consists
of
expanding
the
document
(see
<a class="sec-ref" href="#expanded-document-form">
<span class="secno">
<del class="diff-old">6.14
</del>
<ins class="diff-chg">6.15
</ins>
</span>
<span class="sec-title">
Expanded
Document
Form
</span>
</a>
)
and
then
using
a
developer-supplied
context
to
compact
the
expanded
document.
While
the
context
provided
above
mapped
<code>
http://xmlns.com/foaf/0.1/name
</code>
to
<strong>
name
</strong>,
it
could
have
also
mapped
it
to
any
arbitrary
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
provided
by
the
developer.
This
powerful
mechanism
allows
the
developer
to
re-shape
the
incoming
JSON
data
into
a
format
that
is
optimized
for
their
application.
</p>
</section>
<section id="data-indexing">
<h3>
<span class="secno">
<del class="diff-old">6.16
</del>
<ins class="diff-chg">6.17
</ins>
</span>
Data
Indexing
</h3>
<p>
Databases
are
typically
used
to
make
access
to
data
more
efficient.
Developers
often
extend
this
sort
of
functionality
into
their
application
data
to
deliver
similar
performance
gains.
Often
this
data
does
not
have
any
meaning
from
a
Linked
Data
standpoint,
but
is
still
useful
for
an
application.
</p>
<p>
JSON-LD
introduces
the
notion
of
<a href="#dfn-index-map" title="index-map" class="tref internalDFN">
index
maps
</a>
that
can
be
used
to
structure
data
into
a
form
that
is
more
efficient
to
access.
The
data
indexing
feature
allows
an
author
to
structure
data
using
a
simpley
key-value
map
where
the
keys
do
not
map
to
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>.
This
enables
direct
access
to
data
instead
of
having
to
scan
an
array
in
search
of
a
specific
item.
In
JSON-LD
such
data
can
be
specified
by
associating
the
<code>
@index
</code>
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keyword
</a>
with
a
<code>
@container
</code>
declaration
in
the
context:
</p>
<del class="diff-old">  {
  "@context":
  {
     "schema": "http://schema.org/",
     "name": "schema:name",
     "body": "schema:articleBody",
     "words": "schema:wordCount",
     "post": {
       "@id": "schema:blogPost",

     }
  },
  "@id": "http://example.com/",
  "@type": "schema:Blog",
  "name": "World Financial News",
  "post": {
     "en": {
       "@id": "http://example.com/posts/1/en",
       "body": "World commodities were up today with heavy trading of crude oil...",
       "words": 1539
     },
     "de": {
       "@id": "http://example.com/posts/1/de",
       "body": "Die Werte an Warenbörsen stiegen im Sog eines starken Handels von Rohöl...",
       "words": 1204
     }
  }
</del>
  <div class="example"><div class="example-title"><span>Example 56</span>: Indexing data in JSON-LD</div><pre class="example">{
<ins class="diff-chg">  "@context":
  {
     "schema": "http://schema.org/",
     "name": "schema:name",
     "body": "schema:articleBody",
     "words": "schema:wordCount",
     "post": {
       "@id": "schema:blogPost",
</ins>       <span class="diff">"@container": "@index"</span>
<ins class="diff-chg">
     }
  },
  "@id": "http://example.com/",
  "@type": "schema:Blog",
  "name": "World Financial News",
</ins>  <span class="diff">"post": {
<ins class="diff-chg">
     "en": {
       "@id": "http://example.com/posts/1/en",
       "body": "World commodities were up today with heavy trading of crude oil...",
       "words": 1539
     },
     "de": {
       "@id": "http://example.com/posts/1/de",
       "body": "Die Werte an Warenbörsen stiegen im Sog eines starken Handels von Rohöl...",
       "words": 1204
     }</span>
  }
</ins>
}
</pre>
</div>
<p>
In
the
example
above,
the
<strong>
blogPost
</strong>
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
has
been
marked
as
an
<a href="#dfn-index-map" title="index-map" class="tref internalDFN">
index
map
</a>.
The
<strong>
en
</strong>,
<strong>
de
</strong>,
and
<strong>
ja
</strong>
keys
will
be
ignored
semantically,
but
preserved
syntactically,
by
the
JSON-LD
Processor.
This
allows
a
developer
to
access
the
German
version
of
the
<strong>
blogPost
</strong>
using
the
following
code
snippet:
<code>
obj.blogPost.de
</code>.
</p>
<p>
The
interpretation
of
the
data
above
is
expressed
in
the
table
below.
Note
how
the
index
keys
do
not
appear
in
the
Linked
Data
below,
but
would
continue
to
exist
if
the
document
were
compacted
or
expanded
(see
<a class="sec-ref" href="#compact-document-form">
<span class="secno">
<del class="diff-old">6.15
</del>
<ins class="diff-chg">6.16
</ins>
</span>
<span class="sec-title">
Compact
Document
Form
</span>
</a>
and
<a class="sec-ref" href="#expanded-document-form">
<span class="secno">
<del class="diff-old">6.14
</del>
<ins class="diff-chg">6.15
</ins>
</span>
<span class="sec-title">
Expanded
Document
Form
</span>
</a>
)
using
a
JSON-LD
processor:
</p>
<table class="example">
<thead>
<tr>
<th>
Subject
</th>
<th>
Property
</th>
<th>
Value
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
http://example.com/
</td>
<td>
http://www.w3.org/1999/02/22-rdf-syntax-ns#type
</td>
<td>
http://schema.org/Blog
</td>
</tr>
<tr>
<td>
http://example.com/
</td>
<td>
http://schema.org/name
</td>
<td>
World
Financial
News
</td>
</tr>
<tr>
<td>
http://example.com/
</td>
<td>
http://schema.org/blogPost
</td>
<td>
http://example.com/posts/1/en
</td>
</tr>
<tr>
<td>
http://example.com/
</td>
<td>
http://schema.org/blogPost
</td>
<td>
http://example.com/posts/1/de
</td>
</tr>
<tr>
<td>
http://example.com/posts/1/en
</td>
<td>
http://schema.org/articleBody
</td>
<td>
World
commodities
were
up
today
with
heavy
trading
of
crude
oil...
</td>
</tr>
<tr>
<td>
http://example.com/posts/1/en
</td>
<td>
http://schema.org/wordCount
</td>
<td>
1539
</td>
</tr>
<tr>
<td>
http://example.com/posts/1/de
</td>
<td>
http://schema.org/articleBody
</td>
<td>
Die
Werte
an
Warenbörsen
stiegen
im
Sog
eines
starken
Handels
von
Rohöl...
</td>
</tr>
<tr>
<td>
http://example.com/posts/1/de
</td>
<td>
http://schema.org/wordCount
</td>
<td>
1204
</td>
</tr>
</tbody>
</table>
</section>
</section>
<section id="data-model" class="appendix normative">
<h2>
<span class="secno">
A.
</span>
Data
Model
</h2>
<p>
JSON-LD
is
a
serialization
format
for
<a href="#dfn-linked-data" title="linked-data" class="tref internalDFN">
Linked
Data
</a>
based
on
JSON.
It
is
therefore
important
to
distinguish
between
the
syntax,
which
is
defined
by
JSON
in
[
<cite>
<a href="#bib-RFC4627" class="bibref">
RFC4627
</a>
</cite>
],
and
<dfn id="dfn-json-ld-data-model" title="json-ld-data-model">
JSON-LD's
data
model
</dfn>
which
is
defined
as
follows:
</p>
<ul>
<li>
A
<dfn id="dfn-json-ld-document" title="json-ld-document">
JSON-LD
document
</dfn>
serializes
a
collection
of
<a href="#dfn-json-ld-graph" title="json-ld-graph" class="tref internalDFN">
JSON-LD
graphs
</a>
and
comprises
exactly
one
<dfn id="dfn-default-graph" title="default-graph">
default
graph
</dfn>
and
zero
or
more
<dfn id="dfn-named-graph" title="named-graph">
named
graphs
</dfn>.
</li>
<li>
The
<a href="#dfn-default-graph" title="default-graph" class="tref internalDFN">
default
graph
</a>
does
not
have
a
name
and
<em title="may" class="rfc2119">
may
</em>
be
empty.
</li>
<li>
Each
<a href="#dfn-named-graph" title="named-graph" class="tref internalDFN">
named
graph
</a>
is
a
pair
consisting
of
<del class="diff-old">a
</del>
<ins class="diff-chg">an
</ins><a href="#dfn-iri" title="iri" class="tref internalDFN"><abbr title="Internationalized Resource Identifier"><ins class="diff-chg">
IRI
</ins></abbr></a><ins class="diff-chg">
or
</ins><a href="#dfn-blank-node-identifier" title="blank-node-identifier" class="tref internalDFN"><ins class="diff-chg">
blank
node
identifier
</ins></a><ins class="diff-chg">
(the
</ins><dfn id="dfn-graph-name" title="graph-name">
graph
name
</dfn>
<ins class="diff-new">)
</ins>
and
a
<a href="#dfn-json-ld-graph" title="json-ld-graph" class="tref internalDFN">
JSON-LD
graph
</a>.
<del class="diff-old">The
</del>
<ins class="diff-chg">Whenever
possible,
the
</ins><a href="#dfn-graph-name" title="graph-name" class="tref internalDFN">
graph
name
</a>
<em title="should" class="rfc2119">
should
</em>
be
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
<del class="diff-old">or
blank
node
identifier
</del>
</a>.
</li>
<li>
A
<dfn id="dfn-json-ld-graph" title="json-ld-graph">
JSON-LD
graph
</dfn>
is
a
labeled
directed
<del class="diff-old">graph
containing
</del>
<ins class="diff-chg">graph,
i.e.,
</ins>
a
set
of
<del class="diff-old">zero
or
more
</del>
<a href="#dfn-node" title="node" class="tref internalDFN">
nodes
</a>
connected
by
<a href="#dfn-edge" title="edge" class="tref internalDFN">
edges
</a>.
</li>
<li>
Every
<dfn id="dfn-edge" title="edge">
edge
</dfn>
has
a
direction
associated
with
it
and
is
labeled
with
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
or
a
<a href="#dfn-blank-node-identifier" title="blank-node-identifier" class="tref internalDFN">
blank
node
identifier
</a>.
Within
the
JSON-LD
syntax
these
edge
labels
are
called
<dfn id="dfn-property" title="property">
properties
</dfn>.
<ins class="diff-new">Whenever
possible,
an
</ins><a href="#dfn-edge" title="edge" class="tref internalDFN"><ins class="diff-new">
edge
</ins></a><em title="should" class="rfc2119"><ins class="diff-new">
should
</ins></em><ins class="diff-new">
be
labeled
with
an
</ins><a href="#dfn-iri" title="iri" class="tref internalDFN"><abbr title="Internationalized Resource Identifier"><ins class="diff-new">
IRI
</ins></abbr></a>.
</li>
<li>
Every
<dfn id="dfn-node" title="node">
node
</dfn>
is
<del class="diff-old">either
</del>
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
a
<a href="#dfn-blank-node" title="blank-node" class="tref internalDFN">
blank
node
</a>,
a
<a href="#dfn-json-ld-value" title="json-ld-value" class="tref internalDFN">
JSON-LD
value
</a>,
or
a
<a href="#dfn-list" title="list" class="tref internalDFN">
list
</a>.
</li>
<li>
A
<a href="#dfn-node" title="node" class="tref internalDFN">
node
</a>
having
an
outgoing
edge
<em title="must" class="rfc2119">
must
</em>
be
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
or
a
<a href="#dfn-blank-node" title="blank-node" class="tref internalDFN">
blank
node
</a>.
</li>
<li>
A
<a href="#dfn-json-ld-graph" title="json-ld-graph" class="tref internalDFN">
JSON-LD
graph
</a>
<em title="must not" class="rfc2119">
must
not
</em>
contain
unconnected
<a href="#dfn-node" title="node" class="tref internalDFN">
nodes
</a>,
i.e.,
nodes
which
are
not
connected
by
an
<a href="#dfn-edge" title="edge" class="tref internalDFN">
edge
</a>
to
any
other
<a href="#dfn-node" title="node" class="tref internalDFN">
node
</a>.
</li>
<li>
An
<dfn id="dfn-iri" title="iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</dfn>
(Internationalized
Resource
Identifier)
is
a
string
that
conforms
to
the
syntax
defined
in
[
<cite>
<a href="#bib-RFC3987" class="bibref">
RFC3987
</a>
</cite>
].
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>
used
within
a
<a href="#dfn-json-ld-graph" title="json-ld-graph" class="tref internalDFN">
JSON-LD
graph
</a>
<em title="should" class="rfc2119">
should
</em>
return
a
<a href="#dfn-linked-data" title="linked-data" class="tref internalDFN">
Linked
Data
</a>
document
describing
the
resource
denoted
by
that
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
when
being
dereferenced.
</li>
<li>
A
<dfn id="dfn-blank-node" title="blank-node">
blank
node
</dfn>
is
a
<a href="#dfn-node" title="node" class="tref internalDFN">
node
</a>
which
is
<del class="diff-old">not
</del>
<ins class="diff-chg">neither
</ins>
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
<ins class="diff-new">nor
a
</ins><a href="#dfn-json-ld-value" title="json-ld-value" class="tref internalDFN"><ins class="diff-new">
JSON-LD
value
</ins></a>,<ins class="diff-new">
or
a
</ins><a href="#dfn-list" title="list" class="tref internalDFN"><ins class="diff-new">
list
</ins>
</a>.
A
blank
node
<em title="may" class="rfc2119">
may
</em>
be
identified
using
a
<a href="#dfn-blank-node-identifier" title="blank-node-identifier" class="tref internalDFN">
blank
node
identifier
</a>.
</li>
<li>
A
<dfn id="dfn-blank-node-identifier" title="blank-node-identifier">
blank
node
identifier
</dfn>
is
a
string
that
can
be
used
as
an
identifier
for
a
<a href="#dfn-blank-node" title="blank-node" class="tref internalDFN">
blank
node
</a>
within
the
scope
of
a
<a href="#dfn-json-ld-document" title="json-ld-document" class="tref internalDFN">
JSON-LD
document
</a>.
Blank
node
identifiers
begin
with
<code>
_:
</code>.
</li>
<li>
A
<dfn id="dfn-json-ld-value" title="json-ld-value">
JSON-LD
value
</dfn>
is
a
<a href="#dfn-string" title="string" class="tref internalDFN">
string
</a>,
a
<a href="#dfn-number" title="number" class="tref internalDFN">
number
</a>,
<a href="#dfn-true" title="true" class="tref internalDFN">
true
</a>
or
<a href="#dfn-false" title="false" class="tref internalDFN">
false
</a>,
a
<a href="#dfn-typed-value" title="typed-value" class="tref internalDFN">
typed
value
</a>,
or
a
<a href="#dfn-language-tagged-string" title="language-tagged-string" class="tref internalDFN">
language-tagged
string
</a>.
</li>
<li>
A
<dfn id="dfn-typed-value" title="typed-value">
typed
value
</dfn>
consists
of
a
value,
which
is
a
string,
and
a
type,
which
is
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
<del class="diff-old">.
</del>
</abbr>
</a>.
</li>
<li>
A
<dfn id="dfn-language-tagged-string" title="language-tagged-string">
language-tagged
string
</dfn>
consists
of
a
string
and
a
non-empty
language
tag
as
defined
by
[
<cite>
<a href="#bib-BCP47" class="bibref">
BCP47
</a>
</cite>
].
The
language
tag
<em title="must" class="rfc2119">
must
</em>
be
well-formed
according
to
section
<a href="http://tools.ietf.org/html/bcp47#section-2.2.9">
2.2.9
</a>
of
[
<cite>
<a href="#bib-BCP47" class="bibref">
BCP47
</a>
</cite>
],
and
<em title="must" class="rfc2119">
must
</em>
be
lowercase.
</li>
<li>
A
<dfn id="dfn-list" title="list">
list
</dfn>
is
an
ordered
sequence
of
zero
or
more
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>,
<a href="#dfn-blank-node" title="blank-node" class="tref internalDFN">
blank
nodes
</a>,
and
<a href="#dfn-json-ld-value" title="json-ld-value" class="tref internalDFN">
JSON-LD
values
</a>.
</li>
</ul>
<div class="issue">
<div class="issue-title">
<a href="https://github.com/json-ld/json-ld.org/issues/217">
<span>
Issue
<del class="diff-old">1
</del>
<ins class="diff-chg">217
</ins>
</span>
</a>
</div>
<p class="">
In
contrast
to
the
RDF
data
model
as
defined
in
[
<cite>
<a href="#bib-RDF-CONCEPTS" class="bibref">
RDF-CONCEPTS
</a>
</cite>
],
JSON-LD
allows
blank
nodes
as
property
labels
and
graph
names.
This
feature
is
controversial
in
the
RDF
WG
and
may
be
removed
in
the
future.
</p>
</div>
<p>
<a href="#dfn-json-ld-document" title="json-ld-document" class="tref internalDFN">
JSON-LD
documents
</a>
<em title="may" class="rfc2119">
may
</em>
contain
data
that
cannot
be
represented
by
the
<a href="#dfn-json-ld-data-model" title="json-ld-data-model" class="tref internalDFN">
data
model
</a>
defined
above.
Unless
otherwise
specified,
such
data
is
ignored
when
a
<a href="#dfn-json-ld-document" title="json-ld-document" class="tref internalDFN">
JSON-LD
document
</a>
is
being
processed.
This
means,
e.g.,
that
properties
which
are
not
mapped
to
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
or
<a href="#dfn-blank-node" title="blank-node" class="tref internalDFN">
blank
node
</a>
will
be
ignored.
</p>
<p style="text-align: center">
<img src="linked-data-graph.png" title="An illustration of JSON-LD's data model">
</p>
<p style="text-align: center">
Figure&nbsp;1:
An
illustration
of
JSON-LD's
data
model.
</p>
</section>
<section id="json-ld-grammar" class="appendix normative">
<h2>
<span class="secno">
B.
</span>
JSON-LD
Grammar
</h2>
<em>
This
section
is
normative
</em>
<p>
This
appendix
restates
the
syntactic
conventions
described
in
the
previous
sections
more
formally.
</p>
<div class="note">
<div class="note-title">
<span>
Note
</span>
</div>
<p class="">
The
JSON-LD
context
allows
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keywords
</a>
<a class="sec-ref" href="#aliasing-keywords">
<span class="secno">
<del class="diff-old">6.13
</del>
<ins class="diff-chg">6.14
</ins>
</span>
<span class="sec-title">
Aliasing
Keywords
</span>
</a>
).
Whenever
a
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keyword
</a>
is
discussed
in
this
grammar,
the
statements
also
apply
to
an
alias
for
that
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keyword
</a>.
For
example,
if
the
<a href="#dfn-active-context" title="active-context" class="tref internalDFN">
active
context
</a>
defines
the
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
<code>
id
</code>
as
an
alias
for
<code>
@id
</code>,
that
alias
may
be
legitimately
used
as
a
substitution
for
<code>
@id
</code>.
Note
that
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keyword
</a>
aliases
are
not
expanded
during
context
processing.
</p>
</div>
<p>
A
<a href="#dfn-json-ld-document" title="json-ld-document" class="tref internalDFN">
JSON-LD
document
</a>
<em title="must" class="rfc2119">
must
</em>
be
a
valid
JSON
document
as
described
in
[
<cite>
<a href="#bib-RFC4627" class="bibref">
RFC4627
</a>
</cite>
].
</p>
<p>
A
<a href="#dfn-json-ld-document" title="json-ld-document" class="tref internalDFN">
JSON-LD
document
</a>
<em title="must" class="rfc2119">
must
</em>
be
a
single
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
object
</a>
or
a
JSON
<a href="#dfn-array" title="array" class="tref internalDFN">
array
</a>
containing
a
set
of
one
or
more
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
objects
</a>.
</p>
<section rel="bibo:chapter" resource="#grammar-node-object" typeof="bibo:Chapter" id="grammar-node-object">
<h3>
<span class="secno">
B.1
</span>
Node
Object
</h3>
<p>
A
<dfn id="dfn-node-object" title="node-object">
node
object
</dfn>
represents
zero
or
more
properties
of
a
<a href="#dfn-node" title="node" class="tref internalDFN">
node
</a>
in
the
<a href="#dfn-json-ld-graph" title="json-ld-graph" class="tref internalDFN">
JSON-LD
graph
</a>
serialized
by
the
<a href="#dfn-json-ld-document" title="json-ld-document" class="tref internalDFN">
JSON-LD
document
</a>.
A
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
object
</a>
is
a
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
object
</a>
if
it
exists
outside
of
a
JSON-LD
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
and:
</p>
<ul>
<li>
it
does
not
contain
the
<code>
@value
</code>,
<code>
@list
</code>,
or
<code>
@set
</code>
keywords,
and
</li>
<li>
it
is
not
the
top-most
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
object
</a>
in
the
JSON-LD
document
consisting
of
no
other
members
than
<code>
@graph
</code>
and
<code>
@context
</code>.
</li>
</ul>
<p>
The
<a href="#dfn-property" title="property" class="tref internalDFN">
properties
</a>
of
a
<a href="#dfn-node" title="node" class="tref internalDFN">
node
</a>
in
a
<a href="#dfn-json-ld-graph" title="json-ld-graph" class="tref internalDFN">
JSON-LD
graph
</a>
may
be
spread
among
different
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
objects
</a>
within
a
document.
When
that
happens,
the
keys
of
the
different
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
objects
</a>
are
merged
to
create
the
properties
of
the
resulting
<a href="#dfn-node" title="node" class="tref internalDFN">
node
</a>.
</p>
<p>
A
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
object
</a>
<em title="must" class="rfc2119">
must
</em>
be
a
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
object
</a>.
All
keys
which
are
not
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>,
<a href="#dfn-compact-iri" title="compact-iri" class="tref internalDFN">
compact
IRIs
</a>,
<a href="#dfn-term" title="term" class="tref internalDFN">
terms
</a>
valid
in
the
<a href="#dfn-active-context" title="active-context" class="tref internalDFN">
active
context
</a>,
or
one
of
the
following
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keywords
</a>
<em title="must" class="rfc2119">
must
</em>
be
ignored
when
processed:
</p>
<ul>
<li>
<code>
@context
</code>,
</li>
<li>
<code>
@graph
</code>,
</li>
<li>
<code>
@id
</code>,
</li>
<li>
<code>
@type
</code>,
or
</li>
<li>
<code>
@index
</code>
</li>
</ul>
<p>
If
the
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
object
</a>
contains
the
<code>
@context
</code>
key,
its
value
<em title="must" class="rfc2119">
must
</em>
be
one
of
the
following:
</p>
<ul>
<li>
<a href="#dfn-null" title="null" class="tref internalDFN">
null
</a>,
</li>
<li>
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
</li>
<li>
a
<a href="#dfn-context-definition" title="context-definition" class="tref internalDFN">
context
definition
</a>,
or
</li>
<li>
an
<a href="#dfn-array" title="array" class="tref internalDFN">
array
</a>
composed
of
any
number
of
the
previous
two
expressions.
</li>
</ul>
<p>
If
the
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
object
</a>
contains
the
<code>
@id
</code>
key,
its
value
<em title="must" class="rfc2119">
must
</em>
be
an
<a href="#dfn-absolute-iri" title="absolute-iri" class="tref internalDFN">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
a
<a href="#dfn-relative-iri" title="relative-iri" class="tref internalDFN">
relative
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
or
a
<a href="#dfn-compact-iri" title="compact-iri" class="tref internalDFN">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
(including
<a href="#dfn-blank-node-identifier" title="blank-node-identifier" class="tref internalDFN">
blank
node
identifiers
</a>
).
See
<a class="sec-ref" href="#node-identifiers">
<span class="secno">
5.3
</span>
<span class="sec-title">
Node
Identifiers
</span>
</a>,
<a class="sec-ref" href="#compact-iris">
<span class="secno">
6.1
</span>
<span class="sec-title">
Compact
IRIs
</span>
</a>,
and
<a class="sec-ref" href="#identifying-blank-nodes">
<span class="secno">
<del class="diff-old">6.12
</del>
<ins class="diff-chg">6.13
</ins>
</span>
<span class="sec-title">
Identifying
Blank
Nodes
</span>
</a>
for
further
discussion
on
<code>
@id
</code>
values.
</p>
<p>
If
the
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
object
</a>
contains
the
<code>
@type
</code>
key,
its
value
<em title="must" class="rfc2119">
must
</em>
be
either
an
<a href="#dfn-absolute-iri" title="absolute-iri" class="tref internalDFN">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
a
<a href="#dfn-relative-iri" title="relative-iri" class="tref internalDFN">
relative
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
a
<a href="#dfn-compact-iri" title="compact-iri" class="tref internalDFN">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
(including
<a href="#dfn-blank-node-identifier" title="blank-node-identifier" class="tref internalDFN">
blank
node
identifiers
</a>
),
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
defined
in
the
<a href="#dfn-active-context" title="active-context" class="tref internalDFN">
active
context
</a>
expanding
into
an
<a href="#dfn-absolute-iri" title="absolute-iri" class="tref internalDFN">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
or
an
<a href="#dfn-array" title="array" class="tref internalDFN">
array
</a>
of
any
of
these.
See
<a class="sec-ref" href="#specifying-the-type">
<span class="secno">
5.4
</span>
<span class="sec-title">
Specifying
the
Type
</span>
</a>
for
further
discussion
on
<code>
@type
</code>
values.
</p>
<p>
If
the
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
object
</a>
contains
the
<code>
@graph
</code>
key,
its
value
<em title="must" class="rfc2119">
must
</em>
be
a
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
object
</a>
or
an
<a href="#dfn-array" title="array" class="tref internalDFN">
array
</a>
of
zero
or
more
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
objects
</a>.
If
the
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
object
</a>
contains
an
<code>
@id
</code>
keyword,
its
value
is
used
as
the
label
of
a
named
graph.
See
<a class="sec-ref" href="#named-graphs">
<span class="secno">
<del class="diff-old">6.11
</del>
<ins class="diff-chg">6.12
</ins>
</span>
<span class="sec-title">
Named
Graphs
</span>
</a>
for
further
discussion
on
<code>
@graph
</code>
values.
As
a
special
case,
if
a
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
object
</a>
contains
no
keys
other
than
<code>
@graph
</code>
and
<code>
@context
</code>,
and
the
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
object
</a>
is
the
root
of
the
JSON-LD
document,
the
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
object
</a>
is
not
treated
as
a
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
object
</a>
;
this
is
used
as
a
way
of
defining
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
definitions
</a>
that
may
not
form
a
connected
graph.
This
allows
a
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
to
be
defined
which
is
shared
by
all
of
the
constituent
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
objects
</a>.
</p>
<p>
If
the
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
object
</a>
contains
the
<code>
@index
</code>
key,
its
value
<em title="must" class="rfc2119">
must
</em>
be
a
<a href="#dfn-string" title="string" class="tref internalDFN">
string
</a>.
See
section
<a class="sec-ref" href="#data-indexing">
<span class="secno">
<del class="diff-old">6.16
</del>
<ins class="diff-chg">6.17
</ins>
</span>
<span class="sec-title">
Data
Indexing
</span>
</a>
for
further
discussion
on
<code>
@index
</code>
values.
</p>
<p>
Keys
in
a
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
object
</a>
that
are
not
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keywords
</a>
<em title="must" class="rfc2119">
must
</em>
expand
to
an
<a href="#dfn-absolute-iri" title="absolute-iri" class="tref internalDFN">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
using
the
<a href="#dfn-active-context" title="active-context" class="tref internalDFN">
active
context
</a>.
The
values
associated
with
these
keys
<em title="must" class="rfc2119">
must
</em>
be
one
of
the
following:
</p>
<ul>
<li>
<a href="#dfn-string" title="string" class="tref internalDFN">
string
</a>,
</li>
<li>
<a href="#dfn-number" title="number" class="tref internalDFN">
number
</a>,
</li>
<li>
<a href="#dfn-true" title="true" class="tref internalDFN">
true
</a>,
</li>
<li>
<a href="#dfn-false" title="false" class="tref internalDFN">
false
</a>,
</li>
<li>
<a href="#dfn-null" title="null" class="tref internalDFN">
null
</a>,
</li>
<li>
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
object
</a>,
</li>
<li>
<a href="#dfn-expanded-value" title="expanded-value" class="tref internalDFN">
expanded
value
</a>,
</li>
<li>
<a href="#dfn-list" title="list" class="tref internalDFN">
list
</a>
or
<a href="#dfn-set" title="set" class="tref internalDFN">
set
</a>,
</li>
<li>
an
<a href="#dfn-array" title="array" class="tref internalDFN">
array
</a>
of
zero
or
more
of
the
possibilities
above,
</li>
<li>
a
<a href="#dfn-language-map" title="language-map" class="tref internalDFN">
language
map
</a>,
or
</li>
<li>
an
<a href="#dfn-index-map" title="index-map" class="tref internalDFN">
index
map
</a>
</li>
</ul>
</section>
<section rel="bibo:chapter" resource="#grammar-term-reference" typeof="bibo:Chapter" id="grammar-term-reference">
<h3>
<span class="secno">
B.2
</span>
Term
</h3>
<p>
A
<dfn id="dfn-term" title="term">
term
</dfn>
is
a
short-hand
<a href="#dfn-string" title="string" class="tref internalDFN">
string
</a>
that
expands
to
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
or
a
<a href="#dfn-blank-node-identifier" title="blank-node-identifier" class="tref internalDFN">
blank
node
identifier
</a>.
</p>
<p>
A
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
<em title="must not" class="rfc2119">
must
not
</em>
equal
any
of
the
JSON-LD
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keywords
</a>.
</p>
<p>
To
avoid
forward-compatibility
issues,
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
<em title="should not" class="rfc2119">
should
not
</em>
start
with
an
<code>
@
</code>
character
as
future
versions
of
JSON-LD
may
introduce
additional
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keywords
</a>.
Furthermore,
the
use
of
empty
terms
(
<code>
""
</code>
)
is
discouraged
as
not
all
programming
languages
are
able
to
handle
empty
property
names.
</p>
<p>
See
<a class="sec-ref" href="#the-context">
<span class="secno">
5.1
</span>
<span class="sec-title">
The
Context
</span>
</a>
and
<a class="sec-ref" href="#iris">
<span class="secno">
5.2
</span>
<span class="sec-title">
IRIs
</span>
</a>
for
further
discussion
on
mapping
<a href="#dfn-term" title="term" class="tref internalDFN">
terms
</a>
to
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>.
</p>
</section>
<section rel="bibo:chapter" resource="#grammar-language-map" typeof="bibo:Chapter" id="grammar-language-map">
<h3>
<span class="secno">
B.3
</span>
Language
Map
</h3>
<p>
A
<dfn id="dfn-language-map" title="language-map">
language
map
</dfn>
is
used
to
associate
a
language
with
a
value
in
a
way
that
allows
easy
programmatic
access.
A
<a href="#dfn-language-map" title="language-map" class="tref internalDFN">
language
map
</a>
may
be
used
as
a
term
value
within
a
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
object
</a>
if
the
term
is
defined
with
<code>
@container
</code>
set
to
<code>
@language
</code>.
The
keys
of
a
<a href="#dfn-language-map" title="language-map" class="tref internalDFN">
language
map
</a>
<em title="must" class="rfc2119">
must
</em>
be
lowercase
[
<cite>
<a href="#bib-BCP47" class="bibref">
BCP47
</a>
</cite>
]
<a href="#dfn-string" title="string" class="tref internalDFN">
strings
</a>
with
an
associated
value
that
is
any
of
the
following
types:
</p>
<ul>
<li>
<a href="#dfn-string" title="string" class="tref internalDFN">
string
</a>,
or
</li>
<li>
an
<a href="#dfn-array" title="array" class="tref internalDFN">
array
</a>
of
zero
or
more
strings
</li>
</ul>
<p>
See
<a href="#language-tagged-strings">
</a>
for
further
discussion
on
language
maps.
</p>
</section>
<section rel="bibo:chapter" resource="#grammar-index-map" typeof="bibo:Chapter" id="grammar-index-map">
<h3>
<span class="secno">
B.4
</span>
Index
Map
</h3>
<p>
An
<dfn id="dfn-index-map" title="index-map">
index
map
</dfn>
allows
keys
that
have
no
semantic
meaning,
but
should
be
preserved
regardless,
to
be
used
in
JSON-LD
documents.
An
<a href="#dfn-index-map" title="index-map" class="tref internalDFN">
index
map
</a>
may
be
used
as
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
value
within
a
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
object
</a>
if
the
term
is
defined
with
<code>
@container
</code>
set
to
<code>
@index
</code>.
The
values
of
the
members
of
an
<a href="#dfn-index-map" title="index-map" class="tref internalDFN">
index
map
</a>
<em title="must" class="rfc2119">
must
</em>
be
one
of
the
following
types:
</p>
<ul>
<li>
<a href="#dfn-string" title="string" class="tref internalDFN">
string
</a>,
</li>
<li>
<a href="#dfn-number" title="number" class="tref internalDFN">
number
</a>,
</li>
<li>
<a href="#dfn-true" title="true" class="tref internalDFN">
true
</a>,
</li>
<li>
<a href="#dfn-false" title="false" class="tref internalDFN">
false
</a>,
</li>
<li>
<a href="#dfn-null" title="null" class="tref internalDFN">
null
</a>,
</li>
<li>
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
object
</a>,
</li>
<li>
<a href="#dfn-expanded-value" title="expanded-value" class="tref internalDFN">
expanded
value
</a>,
</li>
<li>
an
<a href="#dfn-array" title="array" class="tref internalDFN">
array
</a>
of
zero
or
more
of
the
above
possibilities
</li>
</ul>
<p>
See
<a class="sec-ref" href="#data-indexing">
<span class="secno">
<del class="diff-old">6.16
</del>
<ins class="diff-chg">6.17
</ins>
</span>
<span class="sec-title">
Data
Indexing
</span>
</a>
for
further
information
on
this
topic.
</p>
</section>
<section rel="bibo:chapter" resource="#grammar-expanded-values" typeof="bibo:Chapter" id="grammar-expanded-values">
<h3>
<span class="secno">
B.5
</span>
Expanded
Values
</h3>
<p>
An
<dfn id="dfn-expanded-value" title="expanded-value">
expanded
value
</dfn>
is
used
to
explicitly
associate
a
type
or
a
language
with
a
value
to
create
a
<a href="#dfn-typed-value" title="typed-value" class="tref internalDFN">
typed
value
</a>
or
a
<a href="#dfn-language-tagged-string" title="language-tagged-string" class="tref internalDFN">
language-tagged
string
</a>.
</p>
<p>
An
<a href="#dfn-expanded-value" title="expanded-value" class="tref internalDFN">
expanded
value
</a>
<em title="must" class="rfc2119">
must
</em>
be
a
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
object
</a>
containing
the
<code>
@value
</code>
key.
It
<em title="may" class="rfc2119">
may
</em>
also
contain
a
<code>
@type
</code>,
a
<code>
@language
</code>,
or
an
<code>
@index
</code>
key
but
<em title="must not" class="rfc2119">
must
not
</em>
contain
both
a
<code>
@type
</code>
and
a
<code>
@language
</code>
key
at
the
same
time.
An
<a href="#dfn-expanded-value" title="expanded-value" class="tref internalDFN">
expanded
value
</a>
<em title="must not" class="rfc2119">
must
not
</em>
contain
keys
other
than
<code>
@value
</code>,
<code>
@type
</code>,
<code>
@language
</code>,
and
<code>
@index
</code>.
An
<a href="#dfn-expanded-value" title="expanded-value" class="tref internalDFN">
expanded
value
</a>
that
contains
a
<code>
@type
</code>
key
is
called
an
<dfn id="dfn-expanded-typed-value" title="expanded-typed-value">
expanded
typed
value
</dfn>.
An
<a href="#dfn-expanded-value" title="expanded-value" class="tref internalDFN">
expanded
value
</a>
that
contains
a
<code>
@language
</code>
key
is
called
an
<dfn id="dfn-expanded-language-tagged-string" title="expanded-language-tagged-string">
expanded
language-tagged
string
</dfn>.
</p>
<p>
The
value
associated
with
the
<code>
@value
</code>
key
<em title="must" class="rfc2119">
must
</em>
be
either
a
<a href="#dfn-string" title="string" class="tref internalDFN">
string
</a>,
<a href="#dfn-number" title="number" class="tref internalDFN">
number
</a>,
<a href="#dfn-true" title="true" class="tref internalDFN">
true
</a>,
<a href="#dfn-false" title="false" class="tref internalDFN">
false
</a>
or
<a href="#dfn-null" title="null" class="tref internalDFN">
null
</a>.
</p>
<p>
The
value
associated
with
the
<code>
@type
</code>
key
<em title="must" class="rfc2119">
must
</em>
be
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>,
a
<a href="#dfn-compact-iri" title="compact-iri" class="tref internalDFN">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
an
<a href="#dfn-absolute-iri" title="absolute-iri" class="tref internalDFN">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
a
<a href="#dfn-relative-iri" title="relative-iri" class="tref internalDFN">
relative
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
or
<a href="#dfn-null" title="null" class="tref internalDFN">
null
</a>.
</p>
<p>
The
value
associated
with
the
<code>
@language
</code>
key
<em title="must" class="rfc2119">
must
</em>
have
the
lexical
form
described
in
[
<cite>
<a href="#bib-BCP47" class="bibref">
BCP47
</a>
</cite>
],
or
be
<a href="#dfn-null" title="null" class="tref internalDFN">
null
</a>.
</p>
<p>
The
value
associated
with
the
<code>
@index
</code>
key
<em title="must" class="rfc2119">
must
</em>
be
a
<a href="#dfn-string" title="string" class="tref internalDFN">
string
</a>.
</p>
<p>
See
<a class="sec-ref" href="#typed-values">
<span class="secno">
6.2
</span>
<span class="sec-title">
Typed
Values
</span>
</a>
and
<a href="#language-tagged-strings">
</a>
for
more
information
on
<a href="#dfn-expanded-value" title="expanded-value" class="tref internalDFN">
expanded
values
</a>.
</p>
</section>
<section rel="bibo:chapter" resource="#grammar-set-list" typeof="bibo:Chapter" id="grammar-set-list">
<h3>
<span class="secno">
B.6
</span>
List
and
Set
Values
</h3>
<p>
A
<a href="#dfn-list" title="list" class="tref internalDFN">
list
</a>
represents
an
<em>
ordered
</em>
set
of
values.
A
<dfn id="dfn-set" title="set">
set
</dfn>
represents
an
<em>
unordered
</em>
set
of
values.
Unless
otherwise
specified,
<a href="#dfn-array" title="array" class="tref internalDFN">
arrays
</a>
are
unordered
in
JSON-LD.
As
such,
the
<code>
@set
</code>
keyword,
when
used
in
the
body
of
a
JSON-LD
document,
represents
just
syntactic
sugar
which
is
optimized
away
when
processing
the
document.
However,
it
is
very
helpful
when
used
within
the
context
of
a
document.
Values
of
terms
associated
with
a
<code>
@set
</code>
or
<code>
@list
</code>
container
will
always
be
represented
in
the
form
of
an
array
when
a
document
is
processed
-
even
if
there
is
just
a
single
value
that
would
otherwise
be
optimized
to
a
non-array
form
in
<a href="#compact-document-form">
compact
document
form
</a>.
This
simplifies
post-processing
of
the
data
as
the
data
is
always
in
array
form.
</p>
<p>
A
<a href="#dfn-list" title="list" class="tref internalDFN">
list
</a>
<em title="must" class="rfc2119">
must
</em>
be
a
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
object
</a>
that
contains
no
other
keys
than
<code>
@list
</code>,
<code>
@context
</code>,
and
<code>
@index
</code>.
</p>
<p>
A
<a href="#dfn-set" title="set" class="tref internalDFN">
set
</a>
<em title="must" class="rfc2119">
must
</em>
be
a
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
object
</a>
that
that
contains
no
other
keys
than
<code>
@set
</code>,
<code>
@context
</code>,
and
<code>
@index
</code>.
Please
note
that
the
<code>
@index
</code>
key
will
be
ignored,
and
thus
be
dropped,
when
being
processed.
</p>
<p>
In
both
cases,
the
value
associated
with
the
keys
<code>
@list
</code>
and
<code>
@set
</code>
<em title="must" class="rfc2119">
must
</em>
be
an
<a href="#dfn-array" title="array" class="tref internalDFN">
array
</a>
of
any
of
the
following:
</p>
<ul>
<li>
<a href="#dfn-string" title="string" class="tref internalDFN">
string
</a>,
</li>
<li>
<a href="#dfn-number" title="number" class="tref internalDFN">
number
</a>,
</li>
<li>
<a href="#dfn-true" title="true" class="tref internalDFN">
true
</a>,
</li>
<li>
<a href="#dfn-false" title="false" class="tref internalDFN">
false
</a>,
</li>
<li>
<a href="#dfn-null" title="null" class="tref internalDFN">
null
</a>,
</li>
<li>
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
object
</a>,
or
</li>
<li>
<a href="#dfn-expanded-value" title="expanded-value" class="tref internalDFN">
expanded
value
</a>
</li>
</ul>
<p>
See
<a class="sec-ref" href="#sets-and-lists">
<span class="secno">
<del class="diff-old">6.9
</del>
<ins class="diff-chg">6.10
</ins>
</span>
<span class="sec-title">
Sets
and
Lists
</span>
</a>
for
further
discussion
on
List
and
Set
Values.
</p>
</section>
<section rel="bibo:chapter" resource="#grammar-context" typeof="bibo:Chapter" id="grammar-context">
<h3>
<span class="secno">
B.7
</span>
Context
Definition
</h3>
<p>
A
<dfn id="dfn-context-definition" title="context-definition">
context
definition
</dfn>
defines
a
<a href="#dfn-local-context" title="local-context" class="tref internalDFN">
local
context
</a>
in
a
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
object
</a>.
</p>
<p>
A
<a href="#dfn-context-definition" title="context-definition" class="tref internalDFN">
context
definition
</a>
<em title="must" class="rfc2119">
must
</em>
be
a
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
object
</a>
containing
one
or
more
key-value
pairs.
Keys
<em title="must" class="rfc2119">
must
</em>
either
be
<a href="#dfn-term" title="term" class="tref internalDFN">
terms
</a>
or
<code>
@language
</code>
or
<code>
@vocab
</code>
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keywords
</a>.
</p>
<p>
If
the
<a href="#dfn-context-definition" title="context-definition" class="tref internalDFN">
context
definition
</a>
has
a
<code>
@language
</code>
key,
its
value
<em title="must" class="rfc2119">
must
</em>
have
the
lexical
form
described
in
[
<cite>
<a href="#bib-BCP47" class="bibref">
BCP47
</a>
</cite>
]
or
be
<a href="#dfn-null" title="null" class="tref internalDFN">
null
</a>.
</p>
<p>
If
the
<a href="#dfn-context-definition" title="context-definition" class="tref internalDFN">
context
definition
</a>
has
a
<code>
@vocab
</code>
key,
its
value
<em title="must" class="rfc2119">
must
</em>
have
the
lexical
form
of
<a href="#dfn-absolute-iri" title="absolute-iri" class="tref internalDFN">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
or
be
<a href="#dfn-null" title="null" class="tref internalDFN">
null
</a>.
</p>
<p>
<a href="#dfn-term" title="term" class="tref internalDFN">
Term
</a>
values
<em title="must" class="rfc2119">
must
</em>
be
either
a
<a href="#dfn-string" title="string" class="tref internalDFN">
string
</a>,
<a href="#dfn-null" title="null" class="tref internalDFN">
null
</a>,
or
an
<a href="#dfn-expanded-term-definition" title="expanded-term-definition" class="tref internalDFN">
expanded
term
definition
</a>.
</p>
<p>
An
<a href="#dfn-expanded-term-definition" title="expanded-term-definition" class="tref internalDFN">
expanded
term
definition
</a>
is
used
to
describe
the
mapping
between
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
and
its
expanded
identifier,
as
well
as
other
properties
of
the
value
associated
with
the
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
when
it
is
used
as
key
in
a
<a href="#dfn-node-object" title="node-object" class="tref internalDFN">
node
object
</a>.
</p>
<p>
An
<a href="#dfn-expanded-term-definition" title="expanded-term-definition" class="tref internalDFN">
expanded
term
definition
</a>
<em title="should" class="rfc2119">
should
</em>
be
a
<a href="#dfn-json-object" title="json-object" class="tref internalDFN">
JSON
object
</a>
composed
of
zero
or
more
keys
from
<code>
@id
</code>,
<code>
@type
</code>,
<code>
@language
</code>
or
<code>
@container
</code>.
An
<a href="#dfn-expanded-term-definition" title="expanded-term-definition" class="tref internalDFN">
expanded
term
definition
</a>
<em title="should not" class="rfc2119">
should
not
</em>
contain
any
other
keys.
</p>
<p>
If
the
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
definition
is
not
<a href="#dfn-null" title="null" class="tref internalDFN">
null
</a>,
a
<a href="#dfn-compact-iri" title="compact-iri" class="tref internalDFN">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
or
an
<a href="#dfn-absolute-iri" title="absolute-iri" class="tref internalDFN">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
and
the
<a href="#dfn-active-context" title="active-context" class="tref internalDFN">
active
context
</a>
does
not
have
an
<code>
@vocab
</code>
mapping,
the
<a href="#dfn-expanded-term-definition" title="expanded-term-definition" class="tref internalDFN">
expanded
term
definition
</a>
<em title="must" class="rfc2119">
must
</em>
include
the
<code>
@id
</code>
key.
</p>
<p>
If
the
<a href="#dfn-expanded-term-definition" title="expanded-term-definition" class="tref internalDFN">
expanded
term
definition
</a>
contains
the
<code>
@id
</code>
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keyword
</a>,
its
value
<em title="must" class="rfc2119">
must
</em>
be
<a href="#dfn-null" title="null" class="tref internalDFN">
null
</a>,
an
<a href="#dfn-absolute-iri" title="absolute-iri" class="tref internalDFN">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
a
<a href="#dfn-blank-node-identifier" title="blank-node-identifier" class="tref internalDFN">
blank
node
identifier
</a>,
a
<a href="#dfn-compact-iri" title="compact-iri" class="tref internalDFN">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
defined
in
the
defining
<a href="#dfn-context-definition" title="context-definition" class="tref internalDFN">
context
definition
</a>
or
the
<a href="#dfn-active-context" title="active-context" class="tref internalDFN">
active
context
</a>,
or
an
<a href="#dfn-array" title="array" class="tref internalDFN">
array
</a>
composed
of
any
of
the
previous
allowed
values
except
<a href="#dfn-null" title="null" class="tref internalDFN">
null
</a>.
</p>
<p>
If
the
<a href="#dfn-expanded-term-definition" title="expanded-term-definition" class="tref internalDFN">
expanded
term
definition
</a>
contains
the
<code>
@type
</code>
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keyword
</a>,
its
value
<em title="must" class="rfc2119">
must
</em>
be
an
<a href="#dfn-absolute-iri" title="absolute-iri" class="tref internalDFN">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
a
<a href="#dfn-compact-iri" title="compact-iri" class="tref internalDFN">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
defined
in
the
defining
<a href="#dfn-context-definition" title="context-definition" class="tref internalDFN">
context
definition
</a>
or
the
<a href="#dfn-active-context" title="active-context" class="tref internalDFN">
active
context
</a>,
<a href="#dfn-null" title="null" class="tref internalDFN">
<ins class="diff-new">null
</ins></a>,
or
the
<ins class="diff-new">one
of
the
</ins><a href="#dfn-keyword" title="keyword" class="tref internalDFN"><ins class="diff-new">
keywords
</ins></a>
<code>
@id
</code>
<del class="diff-old">keyword
.
</del>
<ins class="diff-chg">or
</ins><code><ins class="diff-chg">
@vocab
</ins></code>.
</p>
<p>
If
the
<a href="#dfn-expanded-term-definition" title="expanded-term-definition" class="tref internalDFN">
expanded
term
definition
</a>
contains
the
<code>
@language
</code>
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keyword
</a>,
its
value
<em title="must" class="rfc2119">
must
</em>
have
the
lexical
form
described
in
[
<cite>
<a href="#bib-BCP47" class="bibref">
BCP47
</a>
</cite>
]
or
be
<a href="#dfn-null" title="null" class="tref internalDFN">
null
</a>.
</p>
<p>
If
the
<a href="#dfn-expanded-term-definition" title="expanded-term-definition" class="tref internalDFN">
expanded
term
definition
</a>
contains
the
<code>
@container
</code>
<a href="#dfn-keyword" title="keyword" class="tref internalDFN">
keyword
</a>,
its
value
<em title="must" class="rfc2119">
must
</em>
be
either
<code>
@list
</code>,
<code>
@set
</code>,
<code>
@language
</code>,
<code>
@index
</code>,
or
be
<a href="#dfn-null" title="null" class="tref internalDFN">
null
</a>.
If
the
value
is
<code>
@language
</code>,
when
the
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
is
used
outside
of
the
<code>
@context
</code>,
the
associated
value
<em title="must" class="rfc2119">
must
</em>
be
a
<a href="#dfn-language-map" title="language-map" class="tref internalDFN">
language
map
</a>.
If
the
value
is
<code>
@index
</code>,
when
the
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
is
used
outside
of
the
<code>
@context
</code>,
the
associated
value
<em title="must" class="rfc2119">
must
</em>
be
an
<a href="#dfn-index-map" title="index-map" class="tref internalDFN">
index
map
</a>.
</p>
<p>
<a href="#dfn-term" title="term" class="tref internalDFN">
Terms
</a>
<em title="must not" class="rfc2119">
must
not
</em>
be
used
in
a
circular
manner.
That
is,
the
definition
of
a
term
cannot
depend
on
the
definition
of
another
term
if
that
other
term
also
depends
on
the
first
term.
</p>
<p>
See
<a class="sec-ref" href="#the-context">
<span class="secno">
5.1
</span>
<span class="sec-title">
The
Context
</span>
</a>
for
further
discussion
on
contexts.
</p>
</section>
</section>
<section id="relationship-to-rdf" class="appendix normative">
<h2>
<span class="secno">
C.
</span>
Relationship
to
RDF
</h2>
<p>
The
RDF
data
model,
as
outlined
in
[
<cite>
<a href="#bib-RDF-CONCEPTS" class="bibref">
RDF-CONCEPTS
</a>
</cite>
],
is
an
abstract
syntax
for
representing
a
directed
graph
of
information.
It
is
a
subset
of
<a href="#dfn-json-ld-data-model" title="json-ld-data-model" class="tref internalDFN">
JSON-LD's
data
model
</a>
with
a
few
additional
constraints.
The
differences
between
the
two
data
models
are:
</p>
<ul>
<li>
In
JSON-LD
<a href="#dfn-graph-name" title="graph-name" class="tref internalDFN">
graph
names
</a>
can
be
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>
or
<a href="#dfn-blank-node" title="blank-node" class="tref internalDFN">
blank
nodes
</a>
whereas
in
RDF
graph
names
have
to
be
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>.
</li>
<li>
In
JSON-LD
<a href="#dfn-property" title="property" class="tref internalDFN">
properties
</a>
can
be
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>
or
<a href="#dfn-blank-node" title="blank-node" class="tref internalDFN">
blank
nodes
</a>
whereas
in
RDF
properties
(predicates)
have
to
be
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>.
</li>
<li>
In
JSON-LD
lists
are
part
of
the
data
model
whereas
in
RDF
they
are
part
of
a
vocabulary,
namely
[
<cite>
<a href="#bib-RDF-SCHEMA" class="bibref">
RDF-SCHEMA
</a>
</cite>
].
</li>
<li>
RDF
values
are
either
typed
<em>
literals
</em>
(
<a href="#dfn-typed-value" title="typed-value" class="tref internalDFN">
typed
values
</a>
)
or
<em>
language-tagged
strings
</em>
(
<a href="#dfn-language-tagged-string" title="language-tagged-string" class="tref internalDFN">
language-tagged
strings
</a>
)
whereas
JSON-LD
also
supports
JSON's
native
data
types,
i.e.,
<a href="#dfn-number" title="number" class="tref internalDFN">
number
</a>,
<a href="#dfn-string" title="string" class="tref internalDFN">
strings
</a>,
and
the
boolean
values
<a href="#dfn-true" title="true" class="tref internalDFN">
true
</a>
and
<a href="#dfn-false" title="false" class="tref internalDFN">
false
</a>.
The
JSON-LD
Algorithms
and
API
specification
[
<cite>
<a href="#bib-JSON-LD-API" class="bibref">
JSON-LD-API
</a>
</cite>
]
defines
the
conversion
rules
between
JSON's
native
data
types
and
RDF's
counterparts
to
allow
full
round-tripping.
</li>
</ul>
<p>
Summarized
these
differences
mean
that
JSON-LD
is
capable
of
serializing
any
RDF
graph
or
dataset
and
most,
but
not
all,
JSON-LD
documents
can
be
transformed
to
RDF.
A
complete
description
of
the
algorithms
to
convert
from
RDF
to
JSON-LD
and
from
JSON-LD
to
RDF
is
included
in
the
JSON-LD
Algorithms
and
API
specification
[
<cite>
<a href="#bib-JSON-LD-API" class="bibref">
JSON-LD-API
</a>
</cite>
].
</p>
<p>
Even
though
JSON-LD
serializes
RDF
datasets,
it
can
also
be
used
as
a
RDF
graph
source.
In
that
case,
a
consumer
<em title="must" class="rfc2119">
must
</em>
only
use
the
default
graph
and
ignore
all
named
graphs.
This
allows
servers
to
expose
data
in,
e.g.,
both
Turtle
and
JSON-LD
using
content
negotiation.
</p>
<div class="note">
<div class="note-title">
<span>
Note
</span>
</div>
<p class="">
Publishers
supporting
both
dataset
and
graph
syntaxes
have
to
ensure
that
the
primary
data
is
stored
in
the
default
graph
to
enable
consumers
that
do
not
support
datasets
to
process
the
information.
</p>
</div>
</section>
<section id="relationship-to-other-linked-data-formats" class="appendix informative">
<h2>
<span class="secno">
D.
</span>
Relationship
to
Other
Linked
Data
Formats
</h2>
<p>
<em>
This
section
is
non-normative.
</em>
</p>
<p>
The
JSON-LD
markup
examples
below
demonstrate
how
JSON-LD
can
be
used
to
express
semantic
data
marked
up
in
other
linked
data
formats
such
as
Turtle,
RDFa,
Microformats,
and
Microdata.
These
sections
are
merely
provided
as
evidence
that
JSON-LD
is
very
flexible
in
what
it
can
express
across
different
<a href="#dfn-linked-data" title="linked-data" class="tref internalDFN">
Linked
Data
</a>
approaches.
</p>
<section id="turtle">
<h3>
<span class="secno">
D.1
</span>
Turtle
</h3>
<p>
<em>
This
section
is
non-normative.
</em>
</p>
<p>
The
following
are
examples
of
converting
RDF
expressed
in
<ins class="diff-new">Turtle
</ins>
[
<cite>
<a href="#bib-TURTLE-TR" class="bibref">
TURTLE-TR
</a>
</cite>
]
into
JSON-LD.
</p>
<section id="prefix-definitions">
<h4>
<span class="secno">
D.1.1
</span>
Prefix
definitions
</h4>
<p>
<em>
This
section
is
non-normative.
</em>
</p>
<p>
The
JSON-LD
context
has
direct
equivalents
for
the
Turtle
<code>
@prefix
</code>
declaration:
</p>
<del class="diff-old">@prefix foaf: &lt;http://xmlns.com/foaf/0.1/&gt; .
&lt;http://manu.sporny.org/i/public&gt; a foaf:Person;
  foaf:name "Manu Sporny";
</del>
<div class="example"><div class="example-title"><span>Example 57</span>: A set of statements serialized in Turtle</div><pre class="example">@prefix foaf: &lt;http://xmlns.com/foaf/0.1/&gt; .
<ins class="diff-chg">
&lt;http://manu.sporny.org/i/public&gt; a foaf:Person;
  foaf:name "Manu Sporny";
</ins>
foaf:homepage
&lt;http://manu.sporny.org/&gt;
.
</pre>
</div>
<del class="diff-old">{
  "@context":
  {
    "foaf": "http://xmlns.com/foaf/0.1/"
  },
  "@id": "http://manu.sporny.org/i/public",
  "@type": "foaf:Person",
  "foaf:name": "Manu Sporny",
  "foaf:homepage": { "@id": "http://manu.sporny.org/" }
</del>
<div class="example"><div class="example-title"><span>Example 58</span>: The same set of statements serialized in JSON-LD</div><pre class="example">{
<ins class="diff-chg">  "@context":
  {
    "foaf": "http://xmlns.com/foaf/0.1/"
  },
  "@id": "http://manu.sporny.org/i/public",
  "@type": "foaf:Person",
  "foaf:name": "Manu Sporny",
  "foaf:homepage": { "@id": "http://manu.sporny.org/" }
</ins>
}
</pre>
</div>
<div class="note">
<div class="note-title">
<span>
Note
</span>
</div>
<p class="">
JSON-LD
has
no
equivalent
for
the
Turtle
<code>
@base
</code>
declaration,
but
can
use
a
prefix
such
as
<code>
base
</code>
to
encode
the
information
in
the
document.
</p>
</div>
</section>
<section id="embedding-1">
<h4>
<span class="secno">
D.1.2
</span>
Embedding
</h4>
<p>
Both
Turtle
and
JSON-LD
allow
embedding,
although
Turtle
only
allows
embedding
of
<a href="#dfn-blank-node" title="blank-node" class="tref internalDFN">
blank
nodes
</a>.
</p>
</section>
<del class="diff-old">@prefix foaf: &lt;http://xmlns.com/foaf/0.1/&gt; .
&lt;http://manu.sporny.org/i/public&gt;
  a foaf:Person;
  foaf:name "Manu Sporny";
</del>
<div class="example"><div class="example-title"><span>Example 59</span>: Embedding in Turtle</div><pre class="example">@prefix foaf: &lt;http://xmlns.com/foaf/0.1/&gt; .
<ins class="diff-chg">
&lt;http://manu.sporny.org/i/public&gt;
  a foaf:Person;
  foaf:name "Manu Sporny";
</ins>
foaf:knows
[
a
foaf:Person;
foaf:name
"Gregg
Kellogg"
]
.
</pre>
</div>
<del class="diff-old">{
  "@context":
  {
    "foaf": "http://xmlns.com/foaf/0.1/"
  },
  "@id": "http://manu.sporny.org/i/public",
  "@type": "foaf:Person",
  "foaf:name": "Manu Sporny",
  "foaf:knows":
  {
    "@type": "foaf:Person",
    "foaf:name": "Gregg Kellogg"
  }
</del>
<div class="example"><div class="example-title"><span>Example 60</span>: Same embedding example in JSON-LD</div><pre class="example">{
<ins class="diff-chg">  "@context":
  {
    "foaf": "http://xmlns.com/foaf/0.1/"
  },
  "@id": "http://manu.sporny.org/i/public",
  "@type": "foaf:Person",
  "foaf:name": "Manu Sporny",
  "foaf:knows":
  {
    "@type": "foaf:Person",
    "foaf:name": "Gregg Kellogg"
  }
</ins>
}
</pre>
</div>
<section id="lists">
<h4>
<span class="secno">
D.1.3
</span>
Lists
</h4>
<p>
Both
JSON-LD
and
Turtle
can
represent
sequential
lists
of
values.
</p>
<del class="diff-old">@prefix foaf: &lt;http://xmlns.com/foaf/0.1/&gt; .
&lt;http://example.org/people#joebob&gt; a foaf:Person;
  foaf:name "Joe Bob";
</del>
<div class="example"><div class="example-title"><span>Example 61</span>: A list of values in Turtle</div><pre class="example">@prefix foaf: &lt;http://xmlns.com/foaf/0.1/&gt; .
<ins class="diff-chg">
&lt;http://example.org/people#joebob&gt; a foaf:Person;
  foaf:name "Joe Bob";
</ins>
foaf:nick
(
"joe"
"bob"
"jaybee"
)
.
</pre>
</div>
<del class="diff-old">{
  "@context":
  {
    "foaf": "http://xmlns.com/foaf/0.1/"
  },
  "@id": "http://example.org/people#joebob",
  "@type": "foaf:Person",
  "foaf:name": "Joe Bob",
  "foaf:nick":
  {
    "@list": [ "joe", "bob", "jaybee" ]
  }
</del>
<div class="example"><div class="example-title"><span>Example 62</span>: Same example with a list of values in JSON-LD</div><pre class="example">{
<ins class="diff-chg">  "@context":
  {
    "foaf": "http://xmlns.com/foaf/0.1/"
  },
  "@id": "http://example.org/people#joebob",
  "@type": "foaf:Person",
  "foaf:name": "Joe Bob",
  "foaf:nick":
  {
    "@list": [ "joe", "bob", "jaybee" ]
  }
</ins>
}
</pre>
</div>
</section>
</section>
<section id="rdfa">
<h3>
<span class="secno">
D.2
</span>
RDFa
</h3>
<p>
The
following
example
describes
three
people
with
their
respective
names
and
homepages
in
<ins class="diff-new">RDFa
</ins>
[
<cite>
<a href="#bib-RDFA-CORE" class="bibref">
RDFA-CORE
</a>
</cite>
].
</p>
<del class="diff-old">&gt;
   &lt;ul&gt;
      &lt;li &gt;
        &lt;a &gt;Bob&lt;/a&gt;
      &lt;/li&gt;
      &lt;li &gt;
        &lt;a &gt;Eve&lt;/a&gt;
      &lt;/li&gt;
      &lt;li &gt;
        &lt;a &gt;Manu&lt;/a&gt;
      &lt;/li&gt;
   &lt;/ul&gt;
</del>
<div class="example"><div class="example-title"><span>Example 63</span>: RDFa fragment that describes three people</div><pre class="example">&lt;div <span class="diff">prefix="foaf: http://xmlns.com/foaf/0.1/"</span>&gt;
<ins class="diff-chg">   &lt;ul&gt;
      &lt;li <span class="diff">typeof="foaf:Person"</span>&gt;
        &lt;a <span class="diff">rel="foaf:homepage" href="http://example.com/bob/" property="foaf:name"</span>&gt;Bob&lt;/a&gt;
      &lt;/li&gt;
      &lt;li <span class="diff">typeof="foaf:Person"</span>&gt;
        &lt;a <span class="diff">rel="foaf:homepage" href="http://example.com/eve/" property="foaf:name"</span>&gt;Eve&lt;/a&gt;
      &lt;/li&gt;
      &lt;li <span class="diff">typeof="foaf:Person"</span>&gt;
        &lt;a <span class="diff">rel="foaf:homepage" href="http://example.com/manu/" property="foaf:name"</span>&gt;Manu&lt;/a&gt;
      &lt;/li&gt;
   &lt;/ul&gt;
</ins>
&lt;/div&gt;
</pre>
</div>
<p>
An
example
JSON-LD
implementation
using
a
single
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
is
described
below.
</p>
<del class="diff-old">{
  "@context":
  {
    "foaf": "http://xmlns.com/foaf/0.1/"
  },
  "@graph":
  [
    {
      "@type": "foaf:Person",
      "foaf:homepage": "http://example.com/bob/",
      "foaf:name": "Bob"
    },
    {
      "@type": "foaf:Person",
      "foaf:homepage": "http://example.com/eve/",
      "foaf:name": "Eve"
    },
    {
      "@type": "foaf:Person",
      "foaf:homepage": "http://example.com/manu/",
      "foaf:name": "Manu"
    }
  ]
</del>
<div class="example"><div class="example-title"><span>Example 64</span>: Same description in JSON-LD (context shared among node objects)</div><pre class="example">{
<ins class="diff-chg">  "@context":
  {
    "foaf": "http://xmlns.com/foaf/0.1/"
  },
  "@graph":
  [
    {
      "@type": "foaf:Person",
      "foaf:homepage": "http://example.com/bob/",
      "foaf:name": "Bob"
    },
    {
      "@type": "foaf:Person",
      "foaf:homepage": "http://example.com/eve/",
      "foaf:name": "Eve"
    },
    {
      "@type": "foaf:Person",
      "foaf:homepage": "http://example.com/manu/",
      "foaf:name": "Manu"
    }
  ]
</ins>
}
</pre>
</div>
</section>
<section id="microformats">
<h3>
<span class="secno">
D.3
</span>
Microformats
</h3>
<p>
The
following
example
uses
a
simple
Microformats
hCard
<del class="diff-old">([
</del>
<ins class="diff-chg">example
to
express
how
Microformats
[
</ins>
<cite>
<a href="#bib-MICROFORMATS" class="bibref">
MICROFORMATS
</a>
</cite>
<del class="diff-old">])
example
to
express
how
the
Microformat
is
</del>
<ins class="diff-chg">]
are
</ins>
represented
in
JSON-LD.
</p>
<del class="diff-old">&lt;div class="vcard"&gt;
 &lt;a class="url fn" href="http://tantek.com/"&gt;Tantek Çelik&lt;/a&gt;
</del>
<div class="example"><div class="example-title"><span>Example 65</span>: HTML fragment with a simple Microformats hCard</div><pre class="example">&lt;div class="vcard"&gt;
<ins class="diff-chg"> &lt;a class="url fn" href="http://tantek.com/"&gt;Tantek Çelik&lt;/a&gt;
</ins>
&lt;/div&gt;
</pre>
</div>
<p>
The
representation
of
the
hCard
expresses
the
Microformat
terms
in
the
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
and
uses
them
directly
for
the
<code>
url
</code>
and
<code>
fn
</code>
properties.
Also
note
that
the
Microformat
to
JSON-LD
processor
has
generated
the
proper
URL
type
for
<code>
http://tantek.com/
</code>.
</p>
<del class="diff-old">{
  "@context":
  {
    "vcard": "http://microformats.org/profile/hcard#vcard",
    "url":
    {
      "@id": "http://microformats.org/profile/hcard#url",
      "@type": "@id"
    },
    "fn": "http://microformats.org/profile/hcard#fn"
  },
  "@type": "vcard",
  "url": "http://tantek.com/",
  "fn": "Tantek Çelik"
</del>
<div class="example"><div class="example-title"><span>Example 66</span>: Same hCard representation in JSON-LD</div><pre class="example">{
<ins class="diff-chg">  "@context":
  {
    "vcard": "http://microformats.org/profile/hcard#vcard",
    "url":
    {
      "@id": "http://microformats.org/profile/hcard#url",
      "@type": "@id"
    },
    "fn": "http://microformats.org/profile/hcard#fn"
  },
  "@type": "vcard",
  "url": "http://tantek.com/",
  "fn": "Tantek Çelik"
</ins>
}
</pre>
</div>
</section>
<section id="microdata">
<h3>
<span class="secno">
D.4
</span>
Microdata
</h3>
<p>
The
<ins class="diff-new">HTML
Microdata
</ins>
[
<cite>
<a href="#bib-MICRODATA" class="bibref">
MICRODATA
</a>
</cite>
]
example
below
expresses
book
information
as
a
<del class="diff-old">microdata
</del>
<ins class="diff-chg">Microdata
</ins>
Work
item.
</p>
<del class="diff-old">&lt;dl itemscope
    itemtype="http://purl.org/vocab/frbr/core#Work"
    itemid="http://purl.oreilly.com/works/45U8QJGZSQKDH8N"&gt;
 &lt;dt&gt;Title&lt;/dt&gt;
 &lt;dd&gt;&lt;cite itemprop="http://purl.org/dc/terms/title"&gt;Just a Geek&lt;/cite&gt;&lt;/dd&gt;
 &lt;dt&gt;By&lt;/dt&gt;
 &lt;dd&gt;&lt;span itemprop="http://purl.org/dc/terms/creator"&gt;Wil Wheaton&lt;/span&gt;&lt;/dd&gt;
 &lt;dt&gt;Format&lt;/dt&gt;
 &lt;dd itemprop="http://purl.org/vocab/frbr/core#realization"
     itemscope
     itemtype="http://purl.org/vocab/frbr/core#Expression"
     itemid="http://purl.oreilly.com/products/9780596007683.BOOK"&gt;
  &lt;link itemprop="http://purl.org/dc/terms/type" href="http://purl.oreilly.com/product-types/BOOK"&gt;
  Print
 &lt;/dd&gt;
 &lt;dd itemprop="http://purl.org/vocab/frbr/core#realization"
     itemscope
     itemtype="http://purl.org/vocab/frbr/core#Expression"
     itemid="http://purl.oreilly.com/products/9780596802189.EBOOK"&gt;
  &lt;link itemprop="http://purl.org/dc/terms/type" href="http://purl.oreilly.com/product-types/EBOOK"&gt;
  Ebook
 &lt;/dd&gt;
</del>
<div class="example"><div class="example-title"><span>Example 67</span>: HTML fragments that describes a book using microdata</div><pre class="example">&lt;dl itemscope
<ins class="diff-chg">    itemtype="http://purl.org/vocab/frbr/core#Work"
    itemid="http://purl.oreilly.com/works/45U8QJGZSQKDH8N"&gt;
 &lt;dt&gt;Title&lt;/dt&gt;
 &lt;dd&gt;&lt;cite itemprop="http://purl.org/dc/terms/title"&gt;Just a Geek&lt;/cite&gt;&lt;/dd&gt;
 &lt;dt&gt;By&lt;/dt&gt;
 &lt;dd&gt;&lt;span itemprop="http://purl.org/dc/terms/creator"&gt;Wil Wheaton&lt;/span&gt;&lt;/dd&gt;
 &lt;dt&gt;Format&lt;/dt&gt;
 &lt;dd itemprop="http://purl.org/vocab/frbr/core#realization"
     itemscope
     itemtype="http://purl.org/vocab/frbr/core#Expression"
     itemid="http://purl.oreilly.com/products/9780596007683.BOOK"&gt;
  &lt;link itemprop="http://purl.org/dc/terms/type" href="http://purl.oreilly.com/product-types/BOOK"&gt;
  Print
 &lt;/dd&gt;
 &lt;dd itemprop="http://purl.org/vocab/frbr/core#realization"
     itemscope
     itemtype="http://purl.org/vocab/frbr/core#Expression"
     itemid="http://purl.oreilly.com/products/9780596802189.EBOOK"&gt;
  &lt;link itemprop="http://purl.org/dc/terms/type" href="http://purl.oreilly.com/product-types/EBOOK"&gt;
  Ebook
 &lt;/dd&gt;
</ins>
&lt;/dl&gt;
</pre>
</div>
<p>
Note
that
the
JSON-LD
representation
of
the
Microdata
information
stays
true
to
the
desires
of
the
Microdata
community
to
avoid
contexts
and
instead
refer
to
items
by
their
full
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
</p>
<del class="diff-old">[
  {
    "@id": "http://purl.oreilly.com/works/45U8QJGZSQKDH8N",
    "@type": "http://purl.org/vocab/frbr/core#Work",
    "http://purl.org/dc/terms/title": "Just a Geek",
    "http://purl.org/dc/terms/creator": "Whil Wheaton",
    "http://purl.org/vocab/frbr/core#realization":
    [
      "http://purl.oreilly.com/products/9780596007683.BOOK",
      "http://purl.oreilly.com/products/9780596802189.EBOOK"
    ]
  },
  {
    "@id": "http://purl.oreilly.com/products/9780596007683.BOOK",
    "@type": "http://purl.org/vocab/frbr/core#Expression",
    "http://purl.org/dc/terms/type": "http://purl.oreilly.com/product-types/BOOK"
  },
  {
    "@id": "http://purl.oreilly.com/products/9780596802189.EBOOK",
    "@type": "http://purl.org/vocab/frbr/core#Expression",
    "http://purl.org/dc/terms/type": "http://purl.oreilly.com/product-types/EBOOK"
  }
</del>
<div class="example"><div class="example-title"><span>Example 68</span>: Same book description in JSON-LD (avoiding contexts)</div><pre class="example">[
<ins class="diff-chg">  {
    "@id": "http://purl.oreilly.com/works/45U8QJGZSQKDH8N",
    "@type": "http://purl.org/vocab/frbr/core#Work",
    "http://purl.org/dc/terms/title": "Just a Geek",
    "http://purl.org/dc/terms/creator": "Whil Wheaton",
    "http://purl.org/vocab/frbr/core#realization":
    [
      "http://purl.oreilly.com/products/9780596007683.BOOK",
      "http://purl.oreilly.com/products/9780596802189.EBOOK"
    ]
  },
  {
    "@id": "http://purl.oreilly.com/products/9780596007683.BOOK",
    "@type": "http://purl.org/vocab/frbr/core#Expression",
    "http://purl.org/dc/terms/type": "http://purl.oreilly.com/product-types/BOOK"
  },
  {
    "@id": "http://purl.oreilly.com/products/9780596802189.EBOOK",
    "@type": "http://purl.org/vocab/frbr/core#Expression",
    "http://purl.org/dc/terms/type": "http://purl.oreilly.com/product-types/EBOOK"
  }
</ins>
]
</pre>
</div>
</section>
</section>
<section id="iana-considerations" class="appendix informative">
<h2>
<span class="secno">
E.
</span>
IANA
Considerations
</h2>
<p>
<em>
This
section
is
non-normative.
</em>
</p>
<p>
This
section
is
included
merely
for
standards
community
review
and
will
be
submitted
to
the
Internet
Engineering
Steering
Group
if
this
specification
becomes
a
W3C
Recommendation.
</p>
<h2 id="application-ld-json">
application/ld+json
</h2>
<dl>
<dt>
Type
name:
</dt>
<dd>
application
</dd>
<dt>
Subtype
name:
</dt>
<dd>
ld+json
</dd>
<dt>
Required
parameters:
</dt>
<dd>
None
</dd>
<dt>
Optional
parameters:
</dt>
<dd>
<dl>
<dt>
<code>
profile
</code>
</dt>
<dd>
<p>
A
whitespace-separated
list
of
IRIs
identifying
specific
constraints
or
conventions
that
apply
to
a
JSON-LD
document.
A
profile
<em title="must not" class="rfc2119">
must
not
</em>
change
the
semantics
of
the
resource
<ins class="diff-new">representation
when
processed
without
profile
knowledge,
so
that
clients
both
with
and
without
knowledge
of
a
profiled
resource
can
safely
use
the
same
</ins>
representation.
The
<code>
profile
</code>
parameter
<em title="may" class="rfc2119">
may
</em>
also
be
used
by
clients
to
express
their
preferences
in
the
content
negotiation
process.
It
is
<em title="recommended" class="rfc2119">
recommended
</em>
that
profile
IRIs
are
dereferenceable
and
provide
useful
documentation
at
that
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>.
<ins class="diff-new">For
more
information
and
background
please
refer
to
[
</ins><cite><a href="#bib-PROFILE-LINK" class="bibref"><ins class="diff-new">
PROFILE-LINK
</ins></a></cite><ins class="diff-new">
].
</ins></p><p>
This
specification
defines
four
values
for
the
<code>
profile
</code>
parameter.
To
request
or
specify
Expanded
JSON-LD
document
form,
the
<abbr title="Internationalized Resource Identifier">
<ins class="diff-new">IRI
</ins></abbr>
<code>
http://www.w3.org/ns/json-ld#expanded
</code>
<del class="diff-old">URL
</del>
<em title="should" class="rfc2119">
should
</em>
be
used.
To
request
or
specify
Expanded,
Flattened
JSON-LD
document
form,
the
<abbr title="Internationalized Resource Identifier">
<ins class="diff-new">IRI
</ins></abbr>
<code>
http://www.w3.org/ns/json-ld#expanded-flattened
</code>
<del class="diff-old">URL
</del>
<em title="should" class="rfc2119">
should
</em>
be
used.
To
request
or
specify
Compacted
JSON-LD
document
form,
the
<abbr title="Internationalized Resource Identifier">
<ins class="diff-new">IRI
</ins></abbr>
<code>
http://www.w3.org/ns/json-ld#compacted
</code>
<del class="diff-old">URL
</del>
<em title="should" class="rfc2119">
should
</em>
be
used.
To
request
or
specify
Compacted,
Flattened
JSON-LD
document
form,
the
<abbr title="Internationalized Resource Identifier">
<ins class="diff-new">IRI
</ins></abbr>
<code>
http://www.w3.org/ns/json-ld#compacted-flattened
</code>
<del class="diff-old">URL
</del>
<em title="should" class="rfc2119">
should
</em>
be
used.
<ins class="diff-new">Please
note
that,
according
[
</ins><cite><a href="#bib-HTTP11" class="bibref"><ins class="diff-new">
HTTP11
</ins></a></cite><ins class="diff-new">
],
the
value
of
the
</ins><code><ins class="diff-new">
profile
</ins></code><ins class="diff-new">
parameter
has
to
be
enclosed
in
quotes
(
</ins><code><ins class="diff-new">
"
</ins></code><ins class="diff-new">
)
because
it
contains
special
characters
and,
in
some
cases,
whitespace.
</ins></p>
</dd>
</dl>
</dd>
<dt>
Encoding
considerations:
</dt>
<dd>
<del class="diff-old">The
same
as
the
application/json
MIME
media
type.
</del>
<ins class="diff-chg">See
RFC&nbsp;6839,
section
3.1.
</ins>
</dd>
<dt>
Security
considerations:
</dt>
<dd>
Since
JSON-LD
is
intended
to
be
a
pure
data
exchange
format
for
directed
graphs,
the
serialization
<em title="should not" class="rfc2119">
should
not
</em>
be
passed
through
a
code
execution
mechanism
such
as
JavaScript's
<code>
eval()
</code>
<del class="diff-old">function.
It
is
recommended
that
a
conforming
parser
does
not
attempt
</del>
<ins class="diff-chg">function
</ins>
to
<del class="diff-old">directly
evaluate
the
JSON-LD
serialization
and
instead
purely
parse
the
input
into
a
language-native
data
structure.
</del>
<ins class="diff-chg">be
parsed.
</ins>
<br>
JSON-LD
contexts
that
are
loaded
from
the
Web
over
non-secure
connections,
such
as
HTTP,
run
the
risk
of
modifying
the
JSON-LD
<a href="#dfn-active-context" title="active-context" class="tref internalDFN">
active
context
</a>
in
a
way
that
could
compromise
security.
It
is
advised
that
any
application
that
depends
on
a
remote
context
for
mission
critical
purposes
vet
and
cache
the
remote
context
before
allowing
the
system
to
use
it.
<br>
<ins class="diff-new">JSON-LD
allows
the
substitution
of
long
IRIs
with
short
terms
and
the
compression
of
multiple
properties
into
a
single
property
generator.
Therefore,
JSON-LD
documents
may
expand
enormously
when
processed
and,
in
the
worst
case,
the
resulting
data
might
consume
all
of
the
recipient's
resources.
Applications
should
treat
any
data
with
due
skepticism.
</ins>
</dd>
<dt>
Interoperability
considerations:
</dt>
<dd>
Not
Applicable
</dd>
<dt>
Published
specification:
</dt>
<dd>
The
<a href="http://json-ld.org/spec/latest/">
JSON-LD
</a>
specification.
</dd>
<dt>
Applications
that
use
this
media
type:
</dt>
<dd>
Any
programming
environment
that
requires
the
exchange
of
directed
graphs.
Implementations
of
JSON-LD
have
been
created
for
JavaScript,
Python,
Ruby,
PHP,
and
C++.
</dd>
<dt>
Additional
information:
</dt>
<dd>
<dl>
<dt>
Magic
number(s):
</dt>
<dd>
Not
Applicable
</dd>
<dt>
File
extension(s):
</dt>
<dd>.jsonld
</dd>
<dt>
Macintosh
file
type
code(s):
</dt>
<dd>
TEXT
</dd>
</dl>
</dd>
<dt>
Person
&amp;
email
address
to
contact
for
further
information:
</dt>
<dd>
Manu
Sporny
&lt;msporny@digitalbazaar.com&gt;
</dd>
<dt>
Intended
usage:
</dt>
<dd>
Common
</dd>
<dt>
Restrictions
on
usage:
</dt>
<dd>
None
</dd>
<dt>
Author(s):
</dt>
<dd>
Manu
Sporny,
Dave
Longley,
Gregg
Kellogg,
Markus
Lanthaler,
Niklas
Lindström
</dd>
<dt>
Change
controller:
</dt>
<dd>
W3C
</dd>
</dl>
<p>
Fragment
identifiers
used
with
<a href="#application-ld-json">
application/ld+json
</a>
resources
<em title="may" class="rfc2119">
may
</em>
identify
a
node
in
a
<a href="#dfn-json-ld-graph" title="json-ld-graph" class="tref internalDFN">
JSON-LD
graph
</a>
expressed
in
the
resource.
This
idiom,
which
is
also
used
in
RDF
[
<cite>
<a href="#bib-RDF-CONCEPTS" class="bibref">
RDF-CONCEPTS
</a>
</cite>
],
gives
a
simple
way
to
"mint"
new,
document-local
IRIs
to
label
nodes
and
therefore
contributes
considerably
to
the
expressive
power
of
JSON-LD.
</p>
</section>
<section id="acknowledgements" class="appendix informative">
<h2>
<span class="secno">
F.
</span>
Acknowledgements
</h2>
<p>
<em>
This
section
is
non-normative.
</em>
</p>
<p>
The
authors
would
like
to
extend
a
deep
appreciation
and
the
most
sincere
thanks
to
Mark
Birbeck,
who
contributed
foundational
concepts
to
JSON-LD
via
his
work
on
RDFj.
JSON-LD
uses
a
number
of
core
concepts
introduced
in
RDFj,
such
as
the
context
as
a
mechanism
to
provide
an
environment
for
interpreting
JSON
data.
Mark
had
also
been
very
involved
in
the
work
on
RDFa
as
well.
RDFj
built
upon
that
work.
JSON-LD
exists
because
of
the
work
and
ideas
he
started
nearly
a
decade
ago
in
2004.
</p>
<p>
A
large
amount
of
thanks
goes
out
to
the
JSON-LD
Community
Group
participants
who
worked
through
many
of
the
technical
issues
on
the
mailing
list
and
the
weekly
telecons
-
of
special
mention
are
François
Daoust,
Stéphane
Corlosquet,
Lin
Clark,
and
Zdenko
'Denny'
Vrandečić.
</p>
<p>
The
work
of
David
I.
Lehn
and
Mike
Johnson
are
appreciated
for
reviewing,
and
performing
several
early
implementations
of
the
specification.
Thanks
also
to
Ian
Davis
for
this
work
on
RDF/JSON.
</p>
<p>
Thanks
to
the
following
individuals,
in
order
of
their
first
name,
for
their
input
on
the
specification:
Adrian
Walker,
Alexandre
Passant,
Andy
Seaborne,
Ben
Adida,
Blaine
Cook,
Bradley
Allen,
Brian
Peterson,
Bryan
Thompson,
Conal
Tuohy,
Dan
Brickley,
Danny
Ayers,
Daniel
Leja,
Dave
Reynolds,
David
I.
Lehn,
David
Wood,
Dean
Landolt,
Ed
Summers,
elf
Pavlik,
Eric
Prud'hommeaux,
<ins class="diff-new">Erik
Wilde,
</ins>
Fabian
Christ,
Jon
A.
Frost,
Gavin
Carothers,
Glenn
McDonald,
Guus
Schreiber,
Henri
Bergius,
Jose
María
Alvarez
Rodríguez,
Ivan
Herman,
Jack
Moffitt,
Josh
Mandel,
KANZAKI
Masahide,
Kingsley
Idehen,
Kuno
Woudt,
Larry
Garfield,
Mark
Baker,
Mark
MacGillivray,
Marko
Rodriguez,
Melvin
Carvalho,
Nathan
Rixham,
Olivier
Grisel,
Paolo
Ciccarese,
Pat
Hayes,
Patrick
Logan,
<ins class="diff-new">Paul
Kuykendall,
</ins>
Pelle
Braendgaard,
Peter
Williams,
Pierre-Antoine
Champin,
Richard
Cyganiak,
Roy
T.
Fielding,
Sandro
Hawke,
Srecko
Joksimovic,
Stephane
Fellah,
Steve
Harris,
Ted
Thibodeau
Jr.,
Thomas
Steiner,
Tim
Bray,
Tom
Morris,
Tristan
King,
Sergio
Fernández,
Werner
Wilms,
and
William
<del class="diff-old">Waites
</del>
<ins class="diff-chg">Waites.
</ins>
</p>
</section>
<section rel="bibo:chapter" resource="#references" typeof="bibo:Chapter" class="appendix" id="references">
<h2>
<span class="secno">
G.
</span>
References
</h2>
<section rel="bibo:chapter" resource="#normative-references" typeof="bibo:Chapter" id="normative-references">
<h3>
<span class="secno">
G.1
</span>
Normative
references
</h3>
<dl about="" class="bibliography">
<dt id="bib-BCP47">
[BCP47]
</dt>
<dd rel="dcterms:requires">
A.
Phillips;
M.
Davis.
<a href="http://tools.ietf.org/html/bcp47">
<cite>
Tags
for
Identifying
Languages
</cite>
</a>.
September
2009.
IETF
Best
Current
Practice.
URL:
<a href="http://tools.ietf.org/html/bcp47">
http://tools.ietf.org/html/bcp47
</a>
</dd>
<dt id="bib-RDF-CONCEPTS">
[RDF-CONCEPTS]
</dt>
<dd rel="dcterms:requires">
Richard
Cyganiak,
David
Wood,
Editors.
<cite>
<a href="http://www.w3.org/TR/2013/WD-rdf11-concepts-20130115/">
RDF
1.1
Concepts
and
Abstract
Syntax.
</a>
</cite>
15
January
2013.
W3C
Working
Draft
(work
in
progress).
URL:
<a href="http://www.w3.org/TR/2013/WD-rdf11-concepts-20130115/">
http://www.w3.org/TR/2013/WD-rdf11-concepts-20130115/
</a>
</dd>
<dt id="bib-RFC2119">
[RFC2119]
</dt>
<dd rel="dcterms:requires">
S.
Bradner.
<a href="http://www.ietf.org/rfc/rfc2119.txt">
<cite>
Key
words
for
use
in
RFCs
to
Indicate
Requirement
Levels.
</cite>
</a>
March
1997.
Internet
RFC
2119.
URL:
<a href="http://www.ietf.org/rfc/rfc2119.txt">
http://www.ietf.org/rfc/rfc2119.txt
</a>
</dd>
<dt id="bib-RFC3987">
[RFC3987]
</dt>
<dd rel="dcterms:requires">
M.
Dürst;
M.
Suignard.
<a href="http://www.ietf.org/rfc/rfc3987.txt">
<cite>
Internationalized
Resource
Identifiers
<del class="diff-old">(IRIs).
</del>
<ins class="diff-chg">(IRIs)
</ins>
</cite>
</a>.
January
2005.
<del class="diff-old">Internet
</del>
RFC
3987.
URL:
<a href="http://www.ietf.org/rfc/rfc3987.txt">
http://www.ietf.org/rfc/rfc3987.txt
</a>
</dd>
<dt id="bib-RFC4627">
[RFC4627]
</dt>
<dd rel="dcterms:requires">
D.
Crockford.
<a href="http://www.ietf.org/rfc/rfc4627.txt">
<cite>
The
application/json
Media
Type
for
JavaScript
Object
Notation
(JSON)
</cite>
</a>.
July
2006.
<del class="diff-old">Internet
</del>
RFC
4627.
URL:
<a href="http://www.ietf.org/rfc/rfc4627.txt">
http://www.ietf.org/rfc/rfc4627.txt
</a>
</dd>
<dt id="bib-RFC5988">
[RFC5988]
</dt>
<dd rel="dcterms:requires">
M.
Nottingham,
Editor.
<cite>
<a href="http://tools.ietf.org/rfc/rfc5988">
Web
Linking
</a>.
</cite>
October
2010.
Internet
RFC
5988.
URL:
<a href="http://tools.ietf.org/rfc/rfc5988.txt">
http://tools.ietf.org/rfc/rfc5988.txt
</a>
</dd>
</dl>
</section>
<section rel="bibo:chapter" resource="#informative-references" typeof="bibo:Chapter" id="informative-references">
<h3>
<span class="secno">
G.2
</span>
Informative
references
</h3>
<dl about="" class="bibliography">
<dt id="bib-HTTP11">
<ins class="diff-chg">[HTTP11]
</ins></dt><dd rel="dcterms:references"><ins class="diff-chg">
R.
Fielding
et
al.
</ins><a href="http://www.ietf.org/rfc/rfc2616.txt"><cite><ins class="diff-chg">
Hypertext
Transfer
Protocol
-
HTTP/1.1
</ins></cite></a>.<ins class="diff-chg">
June
1999.
RFC
2616.
URL:
</ins><a href="http://www.ietf.org/rfc/rfc2616.txt"><ins class="diff-chg">
http://www.ietf.org/rfc/rfc2616.txt
</ins></a></dd>
<dt id="bib-JSON-LD-API">
[JSON-LD-API]
</dt>
<dd rel="dcterms:references">
Markus
Lanthaler,
Gregg
Kellogg,
Manu
Sporny,
Editors.
<cite>
<a href="http://json-ld.org/spec/latest/json-ld-api/">
JSON-LD
1.0
Processing
Algorithms
and
API
</a>.
</cite>
W3C
Editor's
Draft
(work
in
progress).
URL:
<a href="http://json-ld.org/spec/latest/json-ld-api/">
http://json-ld.org/spec/latest/json-ld-api/
</a>
</dd>
<dt id="bib-MICRODATA">
[MICRODATA]
</dt>
<dd rel="dcterms:references">
Ian
Hickson,
Editor.
<cite>
<a href="http://www.w3.org/TR/2012/WD-microdata-20120329/">
HTML
Microdata
</a>.
</cite>
29
March
2012.
W3C
Working
Draft
(work
in
progress).
URL:
<a href="http://www.w3.org/TR/2012/WD-microdata-20120329/">
http://www.w3.org/TR/2012/WD-microdata-20120329/
</a>
</dd>
<dt id="bib-MICROFORMATS">
[MICROFORMATS]
</dt>
<dd rel="dcterms:references">
<a href="http://microformats.org">
<cite>
Microformats
</cite>
</a>.
URL:
<a href="http://microformats.org">
http://microformats.org
</a>
</dd>
<dt id="bib-PROFILE-LINK">
<ins class="diff-new">[PROFILE-LINK]
</ins></dt><dd rel="dcterms:references"><ins class="diff-new">
Erik
Wilde.
</ins><cite><a href="http://tools.ietf.org/html/draft-wilde-profile-link"><ins class="diff-new">
The
'profile'
Link
Relation
Type
</ins></a>.</cite><ins class="diff-new">
17
October
2012.
IETF
Internet
Draft
(work
in
progress).
URL:
</ins><a href="http://tools.ietf.org/html/draft-wilde-profile-link"><ins class="diff-new">
http://tools.ietf.org/html/draft-wilde-profile-link
</ins></a></dd>
<dt id="bib-RDF-SCHEMA">
[RDF-SCHEMA]
</dt>
<dd rel="dcterms:references">
Dan
Brickley;
Ramanathan
V.
Guha.
<a href="http://www.w3.org/TR/2004/REC-rdf-schema-20040210">
<cite>
RDF
Vocabulary
Description
Language
1.0:
RDF
<del class="diff-old">Schema.
</del>
<ins class="diff-chg">Schema
</ins>
</cite>
</a>.
10
February
2004.
W3C
Recommendation.
URL:
<a href="http://www.w3.org/TR/2004/REC-rdf-schema-20040210">
http://www.w3.org/TR/2004/REC-rdf-schema-20040210
</a>
</dd>
<dt id="bib-RDFA-CORE">
[RDFA-CORE]
</dt>
<dd rel="dcterms:references">
Shane
<del class="diff-old">McCarron;
</del>
<ins class="diff-chg">McCarron
</ins>
et
al.
<a href="http://www.w3.org/TR/2012/REC-rdfa-core-20120607/">
<cite>
RDFa
Core
1.1:
Syntax
and
processing
rules
for
embedding
RDF
through
<del class="diff-old">attributes.
</del>
<ins class="diff-chg">attributes
</ins>
</cite>
</a>.
7
June
2012.
W3C
Recommendation.
URL:
<a href="http://www.w3.org/TR/2012/REC-rdfa-core-20120607/">
http://www.w3.org/TR/2012/REC-rdfa-core-20120607/
</a>
</dd>
<dt id="bib-TURTLE-TR">
[TURTLE-TR]
</dt>
<dd rel="dcterms:references">
Eric
Prud'hommeaux,
Gavin
Carothers,
Editors.
<cite>
<a href="http://www.w3.org/TR/2011/WD-turtle-20110809/">
Turtle:
Terse
RDF
Triple
Language.
</a>
</cite>
09
August
2011.
W3C
Working
Draft
(work
in
progress).
URL:
<a href="http://www.w3.org/TR/2011/WD-turtle-20110809/">
http://www.w3.org/TR/2011/WD-turtle-20110809/
</a>
</dd>
</dl>
</section>
</section>
</body>
</html>
